Snapshot Backup Question.

Harishkumar .Pathangay

Snapshot Backup Question.

hi,

this is a general question on snapshot backup.

If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.

You ultimately need the original volume in place and the snapped volume to restore the data back.

How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.

 

What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].

or Does the storage device invoke some kind of volume mirroring during lean times?

Is my understanding correct? 

thanks,

harish pathangay

Nadir Doctor

Snapshot Backup Question.
(in response to Harishkumar .Pathangay)
Hi Harish,

Usually snapshot backups are done for large multi-terabyte databases to
minimize recovery time and the software [plus associated storage hardware]
is more expensive.

The original volume is not necessarily needed - for example, if there is a
hardware-related disk issue. Often multiple snapshots are taken every day
[like every 8 hours as an example] since delta changes are recorded at
storage level. Depending on backup retention policies, storage can be
reused appropriately. It is always good to continue doing traditional
backups in case recovery via snapshot doesn't prove successful.

There are only a couple of vendors providing good support for DB2 LUW - IBM
and EMC to name a few. Their product documentation provides scanty details
on technology since proprietary but architecture diagrams provide a good
overall view on available functionality. With our vendor, we found several
bugs during validation and received some helpful patches though it took a
while to receive them.

Hope this helps.


Best Regards,
Nadir



On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <
[login to unmask email]> wrote:

> hi,
>
> this is a general question on snapshot backup.
>
> If I use DB2 ACS API, it just tells to Storage device to take snapshot
> backup of database file systems/LVM/VGs etc.
>
> You ultimately need the original volume in place and the snapped volume to
> restore the data back.
>
> How do you address the issue, if some thing happens on original volume?
> like deletion of some file container like that.
>
>
>
> What I am asking is a snap shot volume backup does not contain the actual
> data like a traditional backup image[001,002 etc files].
>
> or Does the storage device invoke some kind of volume mirroring during
> lean times?
>
> Is my understanding correct?
>
> thanks,
>
> harish pathangay
>
> -----End Original Message-----
>

Harishkumar .Pathangay

Snapshot Backup Question.
(in response to Nadir Doctor)
Hi,
My Question is precisely here [To Quote your words]:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level

Exactly my question is around that point. You take multiple snap shots which are recording delta changes at a file system level. You need still the original volume or file system intact in its place with the base data. Right?

What I am asking is – like snap shot backups are by itself not a self contained unit like the traditional backup image right? That is precise question. You got 2 volumes – one with base and another with delta changes. Now you need them both.

In other words, if I delete a file container from db2 volume group, I can restore the backup image and get all the data back in traditional backup image.
But if I have a snap shot backup taken and mistakenly I delete a file container from db2 volume group, it cannot restore it from a snap shot backup right? Because I deleted in the base volume right. What will I do with delta changes are recorded at storage level. It will not help in recovery right?

Am I getting this correct?

I am asking it for learning purpose only. I do not have any environment.

Thanks,
Harish Pathangay

Sent from Mail for Windows 10

From: Nadir Doctor
Sent: 13 May 2017 22:48
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.

Hi Harish,

Usually snapshot backups are done for large multi-terabyte databases to minimize recovery time and the software [plus associated storage hardware] is more expensive.

The original volume is not necessarily needed - for example, if there is a hardware-related disk issue. Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level. Depending on backup retention policies, storage can be reused appropriately. It is always good to continue doing traditional backups in case recovery via snapshot doesn't prove successful.

There are only a couple of vendors providing good support for DB2 LUW - IBM and EMC to name a few. Their product documentation provides scanty details on technology since proprietary but architecture diagrams provide a good overall view on available functionality. With our vendor, we found several bugs during validation and received some helpful patches though it took a while to receive them.

Hope this helps.


Best Regards,
Nadir
 


On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <[login to unmask email]> wrote:
hi,
this is a general question on snapshot backup.
If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.
You ultimately need the original volume in place and the snapped volume to restore the data back.
How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.
 
What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].
or Does the storage device invoke some kind of volume mirroring during lean times?
Is my understanding correct? 
thanks,
harish pathangay


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and manual efforts compared to typical solutions. Be a hero to your users with BCV5 & XDM. See
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Nadir Doctor

Snapshot Backup Question.
(in response to Harishkumar .Pathangay)
Hi Harish,

Most shops are using db2 automatic storage now and so, the chance of
deletion of some file container is remote. In case you're still using the
classic dms type, I'll encourage consideration of the former due to
advantages of space management being handled by db2 and high watermark
reduction to make space reclamation easier.

Snapshot restore is similar to backup restore - application downtime
involved. Requisite files are overlayed and so, if anything got
accidentally removed, it would be added back after snapshot restore. Usual
case is to choose a specific point-in-time to minimize any possibility of
data loss and often finalized together with application team.

Large databases often don't have lean times - the db2 write suspend and
resume operations complete in about a minute providing a brief "freeze" to
applications which often goes unnoticed. Due to high cost, usage of
snapshot backups for oltp databases which are generally much smaller in
order of magnitude [gb vs tb] is quite rare.


Best Regards,
Nadir



On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <
[login to unmask email]> wrote:

> Hi,
>
> My Question is precisely here [To Quote your words]:
>
> Often multiple snapshots are taken every day [like every 8 hours as an
> example] since delta changes are recorded at storage level
>
>
>
> Exactly my question is around that point. You take multiple snap shots
> which are recording delta changes at a file system level. You need still
> the original volume or file system intact in its place with the base data.
> Right?
>
>
>
> What I am asking is – like snap shot backups are by itself not a self
> contained unit like the traditional backup image right? That is precise
> question. You got 2 volumes – one with base and another with delta changes.
> Now you need them both.
>
>
>
> In other words, if I delete a file container from db2 volume group, I can
> restore the backup image and get all the data back in traditional backup
> image.
>
> But if I have a snap shot backup taken and mistakenly I delete a file
> container from db2 volume group, it cannot restore it from a snap shot
> backup right? Because I deleted in the base volume right. What will I do
> with delta changes are recorded at storage level. It will not help in
> recovery right?
>
>
>
> Am I getting this correct?
>
>
>
> I am asking it for learning purpose only. I do not have any environment.
>
>
>
> Thanks,
>
> Harish Pathangay
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *13 May 2017 22:48
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> Usually snapshot backups are done for large multi-terabyte databases to
> minimize recovery time and the software [plus associated storage hardware]
> is more expensive.
>
>
>
> The original volume is not necessarily needed - for example, if there is a
> hardware-related disk issue. Often multiple snapshots are taken every day
> [like every 8 hours as an example] since delta changes are recorded at
> storage level. Depending on backup retention policies, storage can be
> reused appropriately. It is always good to continue doing traditional
> backups in case recovery via snapshot doesn't prove successful.
>
>
>
> There are only a couple of vendors providing good support for DB2 LUW -
> IBM and EMC to name a few. Their product documentation provides scanty
> details on technology since proprietary but architecture diagrams provide a
> good overall view on available functionality. With our vendor, we found
> several bugs during validation and received some helpful patches though it
> took a while to receive them.
>
>
>
> Hope this helps.
>
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> hi,
>
> this is a general question on snapshot backup.
>
> If I use DB2 ACS API, it just tells to Storage device to take snapshot
> backup of database file systems/LVM/VGs etc.
>
> You ultimately need the original volume in place and the snapped volume to
> restore the data back.
>
> How do you address the issue, if some thing happens on original volume?
> like deletion of some file container like that.
>
>
>
> What I am asking is a snap shot volume backup does not contain the actual
> data like a traditional backup image[001,002 etc files].
>
> or Does the storage device invoke some kind of volume mirroring during
> lean times?
>
> Is my understanding correct?
>
> thanks,
>
> harish pathangay
>
>
>
> *Site Links: *View post online
> http://www.idug.org/p/fo/st/?post=181206&anc=p181206#p181206 View
> mailing list online http://www.idug.org/p/fo/si/?topic=19 Start new
> thread via email <[login to unmask email]> Unsubscribe from this mailing
> list <[login to unmask email]?Subject=Unsubscribe> Manage your
> subscription http://www.idug.org/p/us/to
>
> This email has been sent to: [login to unmask email]
>
> Learn how ESAi's fast data refresh & Test Data Management products can
> save up to 90% in CPU, I/O
> and manual efforts compared to typical solutions. Be a hero to your users
> with BCV5 & XDM. See
> http://www.ESAIGroup.com/idug
>
>
> Use of this email content is governed by the terms of service at:
> http://www.idug.org/p/cm/ld/fid=2
>
>
>
>
>
> -----End Original Message-----
>
>
>
> -----End Original Message-----
>

Harishkumar .Pathangay

Snapshot Backup Question.
(in response to Nadir Doctor)
Hi,

The following statement is what I am not able to understand.

Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore

How? Is it not contradictory to the following words:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level

The Snapshot Backup is actually not backing up any data from the db volume group. It just creates a splice of file system where one mount point is frozen briefly but no actual data movement happens and changes are recorded into another mount point – your delta changes. Right? So with out the base volume how will I get the original deleted file container? Even Auto storage also uses individual container files right.


Thanks,
Harish Pathangay

Sent from Mail for Windows 10

From: Nadir Doctor
Sent: 13 May 2017 23:51
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.

Hi Harish,

Most shops are using db2 automatic storage now and so, the chance of deletion of some file container is remote. In case you're still using the classic dms type, I'll encourage consideration of the former due to advantages of space management being handled by db2 and high watermark reduction to make space reclamation easier.

Snapshot restore is similar to backup restore - application downtime involved. Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore. Usual case is to choose a specific point-in-time to minimize any possibility of data loss and often finalized together with application team.

Large databases often don't have lean times - the db2 write suspend and resume operations complete in about a minute providing a brief "freeze" to applications which often goes unnoticed. Due to high cost, usage of snapshot backups for oltp databases which are generally much smaller in order of magnitude [gb vs tb] is quite rare.


Best Regards,
Nadir
 


On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
My Question is precisely here [To Quote your words]:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
Exactly my question is around that point. You take multiple snap shots which are recording delta changes at a file system level. You need still the original volume or file system intact in its place with the base data. Right?
 
What I am asking is – like snap shot backups are by itself not a self contained unit like the traditional backup image right? That is precise question. You got 2 volumes – one with base and another with delta changes. Now you need them both.
 
In other words, if I delete a file container from db2 volume group, I can restore the backup image and get all the data back in traditional backup image.
But if I have a snap shot backup taken and mistakenly I delete a file container from db2 volume group, it cannot restore it from a snap shot backup right? Because I deleted in the base volume right. What will I do with delta changes are recorded at storage level. It will not help in recovery right?
 
Am I getting this correct?
 
I am asking it for learning purpose only. I do not have any environment.
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 22:48
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Usually snapshot backups are done for large multi-terabyte databases to minimize recovery time and the software [plus associated storage hardware] is more expensive.
 
The original volume is not necessarily needed - for example, if there is a hardware-related disk issue. Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level. Depending on backup retention policies, storage can be reused appropriately. It is always good to continue doing traditional backups in case recovery via snapshot doesn't prove successful.
 
There are only a couple of vendors providing good support for DB2 LUW - IBM and EMC to name a few. Their product documentation provides scanty details on technology since proprietary but architecture diagrams provide a good overall view on available functionality. With our vendor, we found several bugs during validation and received some helpful patches though it took a while to receive them.
 
Hope this helps.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <[login to unmask email]> wrote:
hi,
this is a general question on snapshot backup.
If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.
You ultimately need the original volume in place and the snapped volume to restore the data back.
How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.
 
What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].
or Does the storage device invoke some kind of volume mirroring during lean times?
Is my understanding correct? 
thanks,
harish pathangay
 

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Learn how ESAi's fast data refresh & Test Data Management products can save up to 90% in CPU, I/O
and manual efforts compared to typical solutions. Be a hero to your users with BCV5 & XDM. See
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-----End Original Message-----

 


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and manual efforts compared to typical solutions. Be a hero to your users with BCV5 & XDM. See
http://www.ESAIGroup.com/idug

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Learn how ESAi's fast data refresh & Test Data Management products can save up to 90% in CPU, I/O
and manual efforts compared to typical solutions. Be a hero to your users with BCV5 & XDM. See
http://www.ESAIGroup.com/idug

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Nadir Doctor

Snapshot Backup Question.
(in response to Harishkumar .Pathangay)
Hi Harish,

They are applied cumulatively up to the desired point-in-time for restore -
it completes in fraction of time for large databases instead of usnig
native database backup as restoration is being done quickly in parallel at
storage level.


Best Regards,
Nadir



On Sat, May 13, 2017 at 2:04 PM, Harishkumar .Pathangay <
[login to unmask email]> wrote:

> Hi,
>
>
>
> The following statement is what I am not able to understand.
>
>
>
> Requisite files are overlayed and so, if anything got accidentally
> removed, it would be added back after snapshot restore
>
>
>
> How? Is it not contradictory to the following words:
>
> Often multiple snapshots are taken every day [like every 8 hours as an
> example] since delta changes are recorded at storage level
>
>
>
> The Snapshot Backup is actually not backing up any data from the db volume
> group. It just creates a splice of file system where one mount point is
> frozen briefly but no actual data movement happens and changes are recorded
> into another mount point – your delta changes. Right? So with out the base
> volume how will I get the original deleted file container? Even Auto
> storage also uses individual container files right.
>
>
>
>
>
> Thanks,
>
> Harish Pathangay
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *13 May 2017 23:51
>
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> Most shops are using db2 automatic storage now and so, the chance of
> deletion of some file container is remote. In case you're still using the
> classic dms type, I'll encourage consideration of the former due to
> advantages of space management being handled by db2 and high watermark
> reduction to make space reclamation easier.
>
>
>
> Snapshot restore is similar to backup restore - application downtime
> involved. Requisite files are overlayed and so, if anything got
> accidentally removed, it would be added back after snapshot restore. Usual
> case is to choose a specific point-in-time to minimize any possibility of
> data loss and often finalized together with application team.
>
>
>
> Large databases often don't have lean times - the db2 write suspend and
> resume operations complete in about a minute providing a brief "freeze" to
> applications which often goes unnoticed. Due to high cost, usage of
> snapshot backups for oltp databases which are generally much smaller in
> order of magnitude [gb vs tb] is quite rare.
>
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> Hi,
>
> My Question is precisely here [To Quote your words]:
>
> Often multiple snapshots are taken every day [like every 8 hours as an
> example] since delta changes are recorded at storage level
>
>
>
> Exactly my question is around that point. You take multiple snap shots
> which are recording delta changes at a file system level. You need still
> the original volume or file system intact in its place with the base data.
> Right?
>
>
>
> What I am asking is – like snap shot backups are by itself not a self
> contained unit like the traditional backup image right? That is precise
> question. You got 2 volumes – one with base and another with delta changes.
> Now you need them both.
>
>
>
> In other words, if I delete a file container from db2 volume group, I can
> restore the backup image and get all the data back in traditional backup
> image.
>
> But if I have a snap shot backup taken and mistakenly I delete a file
> container from db2 volume group, it cannot restore it from a snap shot
> backup right? Because I deleted in the base volume right. What will I do
> with delta changes are recorded at storage level. It will not help in
> recovery right?
>
>
>
> Am I getting this correct?
>
>
>
> I am asking it for learning purpose only. I do not have any environment.
>
>
>
> Thanks,
>
> Harish Pathangay
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *13 May 2017 22:48
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> Usually snapshot backups are done for large multi-terabyte databases to
> minimize recovery time and the software [plus associated storage hardware]
> is more expensive.
>
>
>
> The original volume is not necessarily needed - for example, if there is a
> hardware-related disk issue. Often multiple snapshots are taken every day
> [like every 8 hours as an example] since delta changes are recorded at
> storage level. Depending on backup retention policies, storage can be
> reused appropriately. It is always good to continue doing traditional
> backups in case recovery via snapshot doesn't prove successful.
>
>
>
> There are only a couple of vendors providing good support for DB2 LUW -
> IBM and EMC to name a few. Their product documentation provides scanty
> details on technology since proprietary but architecture diagrams provide a
> good overall view on available functionality. With our vendor, we found
> several bugs during validation and received some helpful patches though it
> took a while to receive them.
>
>
>
> Hope this helps.
>
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> hi,
>
> this is a general question on snapshot backup.
>
> If I use DB2 ACS API, it just tells to Storage device to take snapshot
> backup of database file systems/LVM/VGs etc.
>
> You ultimately need the original volume in place and the snapped volume to
> restore the data back.
>
> How do you address the issue, if some thing happens on original volume?
> like deletion of some file container like that.
>
>
>
> What I am asking is a snap shot volume backup does not contain the actual
> data like a traditional backup image[001,002 etc files].
>
> or Does the storage device invoke some kind of volume mirroring during
> lean times?
>
> Is my understanding correct?
>
> thanks,
>
> harish pathangay
>
>
>
> *Site Links: *View post online
> http://www.idug.org/p/fo/st/?post=181206&anc=p181206#p181206 View
> mailing list online http://www.idug.org/p/fo/si/?topic=19 Start new
> thread via email <[login to unmask email]> Unsubscribe from this mailing
> list <[login to unmask email]?Subject=Unsubscribe> Manage your
> subscription http://www.idug.org/p/us/to
>
> This email has been sent to: [login to unmask email]
>
> Learn how ESAi's fast data refresh & Test Data Management products can
> save up to 90% in CPU, I/O
> and manual efforts compared to typical solutions. Be a hero to your users
> with BCV5 & XDM. See
> http://www.ESAIGroup.com/idug
>
>
> Use of this email content is governed by the terms of service at:
> http://www.idug.org/p/cm/ld/fid=2
>
>
>
>
>
> -----End Original Message-----
>
>
>
>
>
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> list <[login to unmask email]?Subject=Unsubscribe> Manage your
> subscription http://www.idug.org/p/us/to
>
> This email has been sent to: [login to unmask email]
>
> Learn how ESAi's fast data refresh & Test Data Management products can
> save up to 90% in CPU, I/O
> and manual efforts compared to typical solutions. Be a hero to your users
> with BCV5 & XDM. See
> http://www.ESAIGroup.com/idug
>
>
> Use of this email content is governed by the terms of service at:
> http://www.idug.org/p/cm/ld/fid=2
>
>
>
>
>
> -----End Original Message-----
>
>
>
> -----End Original Message-----
>

Harishkumar .Pathangay

Snapshot Backup Question.
(in response to Nadir Doctor)
When you apply them cumulatively, where is your db volume group data base line located?
You need that base line volume group or volume still available. ?
Will snap shot backup take a physical copy of all volumes of db2 database into another volume? A Full Baseline Backup? Will this be available in another logical volume?

Is DB2 Snapshot Backup a layer on top of LVM Snapshot Backup? I think this is where my confusion is?

Thanks,
Harish P

Sent from Mail for Windows 10

From: Nadir Doctor
Sent: 14 May 2017 01:45
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.

Hi Harish,

They are applied cumulatively up to the desired point-in-time for restore - it completes in fraction of time for large databases instead of usnig native database backup as restoration is being done quickly in parallel at storage level.



Best Regards,
Nadir
 


On Sat, May 13, 2017 at 2:04 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
 
The following statement is what I am not able to understand.
 
Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore
 
How? Is it not contradictory to the following words:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
The Snapshot Backup is actually not backing up any data from the db volume group. It just creates a splice of file system where one mount point is frozen briefly but no actual data movement happens and changes are recorded into another mount point – your delta changes. Right?  So with out the base volume how will I get the original deleted file container? Even Auto storage also uses individual container files right.
 
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 23:51

To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Most shops are using db2 automatic storage now and so, the chance of deletion of some file container is remote. In case you're still using the classic dms type, I'll encourage consideration of the former due to advantages of space management being handled by db2 and high watermark reduction to make space reclamation easier.
 
Snapshot restore is similar to backup restore - application downtime involved. Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore. Usual case is to choose a specific point-in-time to minimize any possibility of data loss and often finalized together with application team.
 
Large databases often don't have lean times - the db2 write suspend and resume operations complete in about a minute providing a brief "freeze" to applications which often goes unnoticed. Due to high cost, usage of snapshot backups for oltp databases which are generally much smaller in order of magnitude [gb vs tb] is quite rare.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
My Question is precisely here [To Quote your words]:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
Exactly my question is around that point. You take multiple snap shots which are recording delta changes at a file system level. You need still the original volume or file system intact in its place with the base data. Right?
 
What I am asking is – like snap shot backups are by itself not a self contained unit like the traditional backup image right? That is precise question. You got 2 volumes – one with base and another with delta changes. Now you need them both.
 
In other words, if I delete a file container from db2 volume group, I can restore the backup image and get all the data back in traditional backup image.
But if I have a snap shot backup taken and mistakenly I delete a file container from db2 volume group, it cannot restore it from a snap shot backup right? Because I deleted in the base volume right. What will I do with delta changes are recorded at storage level. It will not help in recovery right?
 
Am I getting this correct?
 
I am asking it for learning purpose only. I do not have any environment.
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 22:48
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Usually snapshot backups are done for large multi-terabyte databases to minimize recovery time and the software [plus associated storage hardware] is more expensive.
 
The original volume is not necessarily needed - for example, if there is a hardware-related disk issue. Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level. Depending on backup retention policies, storage can be reused appropriately. It is always good to continue doing traditional backups in case recovery via snapshot doesn't prove successful.
 
There are only a couple of vendors providing good support for DB2 LUW - IBM and EMC to name a few. Their product documentation provides scanty details on technology since proprietary but architecture diagrams provide a good overall view on available functionality. With our vendor, we found several bugs during validation and received some helpful patches though it took a while to receive them.
 
Hope this helps.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <[login to unmask email]> wrote:
hi,
this is a general question on snapshot backup.
If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.
You ultimately need the original volume in place and the snapped volume to restore the data back.
How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.
 
What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].
or Does the storage device invoke some kind of volume mirroring during lean times?
Is my understanding correct? 
thanks,
harish pathangay
 
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Harishkumar .Pathangay

Snapshot Backup Question.
(in response to Harishkumar .Pathangay)
This was the source of my question and why I was not able to understand most of your replies. And getting confused myself over and over again with LVM snapshot too coming into my brain. I was terribly mixing up things and getting confused. KC is huge, to get clarity I had to do lot of reading. The problem is they are not mentioning about this in a text which talk about snapshot backup.

Here is KC Doc [some what cleared my confusion]:

Sample output for a snapshot backup with an active background copy.
db2acsutil query status db f01 instance db2inst1 dbpartitionnum 0

Instance Database Part Image Time Status
========== ========== ==== ============== =======================================
keon14 F01 0 20070719120848 Remotely mountable + Background_monitor
pending (16 / 1024 MB)


When a snap shot backup [DB2 ACS API] is taken, the command just returns quickly only by marking FS with some time stamps or some kind of marking indicating the time freeze for that FS [which is a kind of LVM snap shot concept right]. DB2 ACS API eliminates the need to mention db2 volumes individually used by db2 data base.

The Backup Command just appears to return as if it got completed in 5-10 secs[just saying].
But actual copy of Volume will happen in a background process, which runs separately.

The Backup has become a 2 step process. Once this back ground copy completes, then only we can say in a real sense backup got completed.

If I mistakenly issue delete command to a container file of db2 database, then one of two options can happen.

1. it can prevent such deletion because active back ground copy is going on. It will not allow deletions till job is complete. OR
2. it will mark for deletion , but the file will be internally still available for back ground copy process. Once that completes, the space occupied by file will be deleted internally too.

I do not know what will happen. But either way is fine as of now. I seem to get an over all idea.
But at least I hope this time I got some better understanding.

Any Inputs?

Thanks,
Harish P


Sent from Mail for Windows 10

From: Harishkumar .Pathangay
Sent: 14 May 2017 01:58
To: Nadir Doctor
Subject: [DB2-L] - RE: Snapshot Backup Question.

When you apply them cumulatively, where is your db volume group data base line located?
You need that base line volume group or volume still available. ?
Will snap shot backup take a physical copy of all volumes of db2 database into another volume? A Full Baseline Backup? Will this be available in another logical volume?

Is DB2 Snapshot Backup a layer on top of LVM Snapshot Backup? I think this is where my confusion is?

Thanks,
Harish P  

Sent from Mail for Windows 10

From: Nadir Doctor
Sent: 14 May 2017 01:45
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.

Hi Harish,

They are applied cumulatively up to the desired point-in-time for restore - it completes in fraction of time for large databases instead of usnig native database backup as restoration is being done quickly in parallel at storage level.



Best Regards,
Nadir
 


On Sat, May 13, 2017 at 2:04 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
 
The following statement is what I am not able to understand.
 
Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore
 
How? Is it not contradictory to the following words:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
The Snapshot Backup is actually not backing up any data from the db volume group. It just creates a splice of file system where one mount point is frozen briefly but no actual data movement happens and changes are recorded into another mount point – your delta changes. Right?  So with out the base volume how will I get the original deleted file container? Even Auto storage also uses individual container files right.
 
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 23:51

To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Most shops are using db2 automatic storage now and so, the chance of deletion of some file container is remote. In case you're still using the classic dms type, I'll encourage consideration of the former due to advantages of space management being handled by db2 and high watermark reduction to make space reclamation easier.
 
Snapshot restore is similar to backup restore - application downtime involved. Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore. Usual case is to choose a specific point-in-time to minimize any possibility of data loss and often finalized together with application team.
 
Large databases often don't have lean times - the db2 write suspend and resume operations complete in about a minute providing a brief "freeze" to applications which often goes unnoticed. Due to high cost, usage of snapshot backups for oltp databases which are generally much smaller in order of magnitude [gb vs tb] is quite rare.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
My Question is precisely here [To Quote your words]:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
Exactly my question is around that point. You take multiple snap shots which are recording delta changes at a file system level. You need still the original volume or file system intact in its place with the base data. Right?
 
What I am asking is – like snap shot backups are by itself not a self contained unit like the traditional backup image right? That is precise question. You got 2 volumes – one with base and another with delta changes. Now you need them both.
 
In other words, if I delete a file container from db2 volume group, I can restore the backup image and get all the data back in traditional backup image.
But if I have a snap shot backup taken and mistakenly I delete a file container from db2 volume group, it cannot restore it from a snap shot backup right? Because I deleted in the base volume right. What will I do with delta changes are recorded at storage level. It will not help in recovery right?
 
Am I getting this correct?
 
I am asking it for learning purpose only. I do not have any environment.
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 22:48
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Usually snapshot backups are done for large multi-terabyte databases to minimize recovery time and the software [plus associated storage hardware] is more expensive.
 
The original volume is not necessarily needed - for example, if there is a hardware-related disk issue. Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level. Depending on backup retention policies, storage can be reused appropriately. It is always good to continue doing traditional backups in case recovery via snapshot doesn't prove successful.
 
There are only a couple of vendors providing good support for DB2 LUW - IBM and EMC to name a few. Their product documentation provides scanty details on technology since proprietary but architecture diagrams provide a good overall view on available functionality. With our vendor, we found several bugs during validation and received some helpful patches though it took a while to receive them.
 
Hope this helps.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <[login to unmask email]> wrote:
hi,
this is a general question on snapshot backup.
If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.
You ultimately need the original volume in place and the snapped volume to restore the data back.
How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.
 
What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].
or Does the storage device invoke some kind of volume mirroring during lean times?
Is my understanding correct? 
thanks,
harish pathangay
 
Site Links: View post online   View mailing list online   Start new thread via email   Unsubscribe from this mailing list   Manage your subscription  

This email has been sent to: [login to unmask email]
Learn how ESAi's fast data refresh & Test Data Management products can save up to 90% in CPU, I/O
and manual efforts compared to typical solutions. Be a hero to your users with BCV5 & XDM. See
http://www.ESAIGroup.com/idug

Use of this email content is governed by the terms of service at:
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Nadir Doctor

Snapshot Backup Question.
(in response to Harishkumar .Pathangay)
Hi Harish,

That is what a full database snapshot backup does.

A db2 snapshot backup is basically a full/incremental lvm snapshot backup
for all volume groups associated with both data and logs.


Best Regards,
Nadir



On Sat, May 13, 2017 at 3:28 PM, Harishkumar .Pathangay <
[login to unmask email]> wrote:

> When you apply them cumulatively, where is your db volume group data base
> line located?
>
> You need that base line volume group or volume still available. ?
>
> Will snap shot backup take a physical copy of all volumes of db2 database
> into another volume? A Full Baseline Backup? Will this be available in
> another logical volume?
>
>
>
> Is DB2 Snapshot Backup a layer on top of LVM Snapshot Backup? I think this
> is where my confusion is?
>
>
>
> Thanks,
>
> Harish P
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *14 May 2017 01:45
>
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> They are applied cumulatively up to the desired point-in-time for restore
> - it completes in fraction of time for large databases instead of usnig
> native database backup as restoration is being done quickly in parallel at
> storage level.
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 2:04 PM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> Hi,
>
>
>
> The following statement is what I am not able to understand.
>
>
>
> Requisite files are overlayed and so, if anything got accidentally
> removed, it would be added back after snapshot restore
>
>
>
> How? Is it not contradictory to the following words:
>
> Often multiple snapshots are taken every day [like every 8 hours as an
> example] since delta changes are recorded at storage level
>
>
>
> The Snapshot Backup is actually not backing up any data from the db volume
> group. It just creates a splice of file system where one mount point is
> frozen briefly but no actual data movement happens and changes are recorded
> into another mount point – your delta changes. Right? So with out the base
> volume how will I get the original deleted file container? Even Auto
> storage also uses individual container files right.
>
>
>
>
>
> Thanks,
>
> Harish Pathangay
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *13 May 2017 23:51
>
>
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> Most shops are using db2 automatic storage now and so, the chance of
> deletion of some file container is remote. In case you're still using the
> classic dms type, I'll encourage consideration of the former due to
> advantages of space management being handled by db2 and high watermark
> reduction to make space reclamation easier.
>
>
>
> Snapshot restore is similar to backup restore - application downtime
> involved. Requisite files are overlayed and so, if anything got
> accidentally removed, it would be added back after snapshot restore. Usual
> case is to choose a specific point-in-time to minimize any possibility of
> data loss and often finalized together with application team.
>
>
>
> Large databases often don't have lean times - the db2 write suspend and
> resume operations complete in about a minute providing a brief "freeze" to
> applications which often goes unnoticed. Due to high cost, usage of
> snapshot backups for oltp databases which are generally much smaller in
> order of magnitude [gb vs tb] is quite rare.
>
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> Hi,
>
> My Question is precisely here [To Quote your words]:
>
> Often multiple snapshots are taken every day [like every 8 hours as an
> example] since delta changes are recorded at storage level
>
>
>
> Exactly my question is around that point. You take multiple snap shots
> which are recording delta changes at a file system level. You need still
> the original volume or file system intact in its place with the base data.
> Right?
>
>
>
> What I am asking is – like snap shot backups are by itself not a self
> contained unit like the traditional backup image right? That is precise
> question. You got 2 volumes – one with base and another with delta changes.
> Now you need them both.
>
>
>
> In other words, if I delete a file container from db2 volume group, I can
> restore the backup image and get all the data back in traditional backup
> image.
>
> But if I have a snap shot backup taken and mistakenly I delete a file
> container from db2 volume group, it cannot restore it from a snap shot
> backup right? Because I deleted in the base volume right. What will I do
> with delta changes are recorded at storage level. It will not help in
> recovery right?
>
>
>
> Am I getting this correct?
>
>
>
> I am asking it for learning purpose only. I do not have any environment.
>
>
>
> Thanks,
>
> Harish Pathangay
>
>
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for
> Windows 10
>
>
>
> *From: *Nadir Doctor <[login to unmask email]>
> *Sent: *13 May 2017 22:48
> *To: *[login to unmask email]
> *Subject: *[DB2-L] - RE: Snapshot Backup Question.
>
>
>
> Hi Harish,
>
>
>
> Usually snapshot backups are done for large multi-terabyte databases to
> minimize recovery time and the software [plus associated storage hardware]
> is more expensive.
>
>
>
> The original volume is not necessarily needed - for example, if there is a
> hardware-related disk issue. Often multiple snapshots are taken every day
> [like every 8 hours as an example] since delta changes are recorded at
> storage level. Depending on backup retention policies, storage can be
> reused appropriately. It is always good to continue doing traditional
> backups in case recovery via snapshot doesn't prove successful.
>
>
>
> There are only a couple of vendors providing good support for DB2 LUW -
> IBM and EMC to name a few. Their product documentation provides scanty
> details on technology since proprietary but architecture diagrams provide a
> good overall view on available functionality. With our vendor, we found
> several bugs during validation and received some helpful patches though it
> took a while to receive them.
>
>
>
> Hope this helps.
>
>
>
>
>
> Best Regards,
>
> Nadir
>
>
>
>
>
>
>
> On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <
> [login to unmask email]> wrote:
>
> hi,
>
> this is a general question on snapshot backup.
>
> If I use DB2 ACS API, it just tells to Storage device to take snapshot
> backup of database file systems/LVM/VGs etc.
>
> You ultimately need the original volume in place and the snapped volume to
> restore the data back.
>
> How do you address the issue, if some thing happens on original volume?
> like deletion of some file container like that.
>
>
>
> What I am asking is a snap shot volume backup does not contain the actual
> data like a traditional backup image[001,002 etc files].
>
> or Does the storage device invoke some kind of volume mirroring during
> lean times?
>
> Is my understanding correct?
>
> thanks,
>
> harish pathangay
>
>
>
> *Site Links: *View post online
> http://www.idug.org/p/fo/st/?post=181206&anc=p181206#p181206 View
> mailing list online http://www.idug.org/p/fo/si/?topic=19 Start new
> thread via email <[login to unmask email]> Unsubscribe from this mailing
> list <[login to unmask email]?Subject=Unsubscribe> Manage your
> subscription http://www.idug.org/p/us/to
>
> This email has been sent to: [login to unmask email]
>
> Learn how ESAi's fast data refresh & Test Data Management products can
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Harishkumar .Pathangay

Snapshot Backup Question.
(in response to Nadir Doctor)
I was looking at KC for a long time, but could not see any page describing this. I did ask that question in the very first e-mail.

Thanks,
Harish P

Sent from Mail for Windows 10

From: Nadir Doctor
Sent: 14 May 2017 03:37
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.

Hi Harish,

That is what a full database snapshot backup does.

A db2 snapshot backup is basically a full/incremental lvm snapshot backup for all volume groups associated with both data and logs.



Best Regards,
Nadir
 


On Sat, May 13, 2017 at 3:28 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
When you apply them cumulatively, where is your db volume group data base line located?
You need that base line volume group or volume still available. ?
Will snap shot backup take a physical copy of all volumes of db2 database into another volume? A Full Baseline Backup? Will this be available in another logical volume?
 
Is DB2 Snapshot Backup a layer on top of LVM Snapshot Backup? I think this is where my confusion is?
 
Thanks,
Harish P  
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 14 May 2017 01:45

To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
They are applied cumulatively up to the desired point-in-time for restore - it completes in fraction of time for large databases instead of usnig native database backup as restoration is being done quickly in parallel at storage level.


 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 2:04 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
 
The following statement is what I am not able to understand.
 
Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore
 
How? Is it not contradictory to the following words:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
The Snapshot Backup is actually not backing up any data from the db volume group. It just creates a splice of file system where one mount point is frozen briefly but no actual data movement happens and changes are recorded into another mount point – your delta changes. Right?  So with out the base volume how will I get the original deleted file container? Even Auto storage also uses individual container files right.
 
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 23:51

To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Most shops are using db2 automatic storage now and so, the chance of deletion of some file container is remote. In case you're still using the classic dms type, I'll encourage consideration of the former due to advantages of space management being handled by db2 and high watermark reduction to make space reclamation easier.
 
Snapshot restore is similar to backup restore - application downtime involved. Requisite files are overlayed and so, if anything got accidentally removed, it would be added back after snapshot restore. Usual case is to choose a specific point-in-time to minimize any possibility of data loss and often finalized together with application team.
 
Large databases often don't have lean times - the db2 write suspend and resume operations complete in about a minute providing a brief "freeze" to applications which often goes unnoticed. Due to high cost, usage of snapshot backups for oltp databases which are generally much smaller in order of magnitude [gb vs tb] is quite rare.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 12:54 PM, Harishkumar .Pathangay <[login to unmask email]> wrote:
Hi,
My Question is precisely here [To Quote your words]:
Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level
 
Exactly my question is around that point. You take multiple snap shots which are recording delta changes at a file system level. You need still the original volume or file system intact in its place with the base data. Right?
 
What I am asking is – like snap shot backups are by itself not a self contained unit like the traditional backup image right? That is precise question. You got 2 volumes – one with base and another with delta changes. Now you need them both.
 
In other words, if I delete a file container from db2 volume group, I can restore the backup image and get all the data back in traditional backup image.
But if I have a snap shot backup taken and mistakenly I delete a file container from db2 volume group, it cannot restore it from a snap shot backup right? Because I deleted in the base volume right. What will I do with delta changes are recorded at storage level. It will not help in recovery right?
 
Am I getting this correct?
 
I am asking it for learning purpose only. I do not have any environment.
 
Thanks,
Harish Pathangay
 
Sent from Mail for Windows 10
 
From: Nadir Doctor
Sent: 13 May 2017 22:48
To: [login to unmask email]
Subject: [DB2-L] - RE: Snapshot Backup Question.
 
Hi Harish,
 
Usually snapshot backups are done for large multi-terabyte databases to minimize recovery time and the software [plus associated storage hardware] is more expensive.
 
The original volume is not necessarily needed - for example, if there is a hardware-related disk issue. Often multiple snapshots are taken every day [like every 8 hours as an example] since delta changes are recorded at storage level. Depending on backup retention policies, storage can be reused appropriately. It is always good to continue doing traditional backups in case recovery via snapshot doesn't prove successful.
 
There are only a couple of vendors providing good support for DB2 LUW - IBM and EMC to name a few. Their product documentation provides scanty details on technology since proprietary but architecture diagrams provide a good overall view on available functionality. With our vendor, we found several bugs during validation and received some helpful patches though it took a while to receive them.
 
Hope this helps.
 
 
Best Regards,
Nadir
 
 
 
On Sat, May 13, 2017 at 11:04 AM, Harishkumar .Pathangay <[login to unmask email]> wrote:
hi,
this is a general question on snapshot backup.
If I use DB2 ACS API, it just tells to Storage device to take snapshot backup of database file systems/LVM/VGs etc.
You ultimately need the original volume in place and the snapped volume to restore the data back.
How do you address the issue, if some thing happens on original volume? like deletion of some file container like that.
 
What I am asking is a snap shot volume backup does not contain the actual data like a traditional backup image[001,002 etc files].
or Does the storage device invoke some kind of volume mirroring during lean times?
Is my understanding correct? 
thanks,
harish pathangay
 
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