Flash Copy vs DB2 Utilities

Nick Nur

Flash Copy vs DB2 Utilities
Hi Colleagues
In our ERP environment of 7 x 24 sometimes a backup and recovery needs 6 to 10 hrs duration. Somebody suggested Flash Copy strategy as quick methodology to replace traditional DB2 utilities.
We are at DB2 v8.1 z/OS.
My question to the list:
Can the DBA have an effective Flash Copy strategy to replace normal DB2 utilities of backup and recovery procedures? Is that possible? What is the impact and implications on SYSIBM.SYSCOPY and database administration in general?
Can you please advice, comment and elaborate if you can?
Thank you in advance.
Nick Nur



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Mark McCormack

Flash Copy vs DB2 Utilities
(in response to Nick Nur)
Nick,

I see you have received no replies. You have not asked a simple
question. My answer will leave out many, many details.

At my current employer, we use a variation on flash copy for our normal
backup and recovery processing, and we have been doing it for a number
of years.

Some details on daily backup:
-SET LOG SUSPEND
EMC's variation on flash copy (their jargon is 'business continuity
volume (or bcv) split'). This covers all dasd for the whole DB2
subsystem.
-SET LOG RESUME
Backup of the frozen dasd mirrors to tape via FDR software.
The time from suspend to resume in our case is a few minutes. EMC says
they have variations that run in a few seconds. The tape backups can
take a few hours, but that is offline processing.

Some details on recovery:
-STOP DB(--) SPACE(--)
Recover the vsam data set for the object from the FDR backup tape
file(s) manually. You had best produce some sort of report at backup
time showing which data sets reside on which volumes. Yes. this can be
slow.
-START DB(--) SPACE(--) ACCESS(UT)
Then Recover tablespace LOGONLY (to current or TORBA or TOLOGPOINT)
Then Rebuild index as needed
-START DB(--) SPACE(--) ACCESS(RW)

This was already in use for lots of other mainframe stuff when I arrived
here 8 years ago. The assumption was that it could work for DB2 also.
There are design pieces in DB2 from the beginning that make this
possible. Bottom line: backup is much faster, recovery requires a lot
more work and time. Since we run few recoveries, it works for us. We
run the copy utility rarely, mostly after (or concurrent with) reorg and
load replace.

Do you think this is just for the lunatic fringe? Consider the SYSTEM
BACKUP and RECOVER utilities in DB2v8, aimed mostly at the ERP crowd.
They rely on flash copy or variations from vendors other than IBM. Jim
Teng has new wrinkles in DB2v9 to allow recovery of individual objects.
I suspect that dasd backups will eventually replace individual copy
files for many people. I make no prediction about when. It does
require a lot of coordination between dasd managers and DBAs.

Mark McCormack



The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms

Nick Nur

Re: Flash Copy vs DB2 Utilities
(in response to Mark McCormack)
Thank you Mark.
I shall discuss your reply with my boss and see if we can do something in that area.
Thanks again.
Nick Nur

"McCormack, Mark A" <[login to unmask email]> wrote:
Nick,
I see you have received no replies. You have not asked a simple question. My answer will leave out many, many details.

At my current employer, we use a variation on flash copy for our normal backup and recovery processing, and we have been doing it for a number of years.
Some details on daily backup:
-SET LOG SUSPEND
EMC’s variation on flash copy (their jargon is ‘business continuity volume (or bcv) split’). This covers all dasd for the whole DB2 subsystem.
-SET LOG RESUME
Backup of the frozen dasd mirrors to tape via FDR software.
The time from suspend to resume in our case is a few minutes. EMC says they have variations that run in a few seconds. The tape backups can take a few hours, but that is offline processing.
Some details on recovery:
-STOP DB(--) SPACE(--)
Recover the vsam data set for the object from the FDR backup tape file(s) manually. You had best produce some sort of report at backup time showing which data sets reside on which volumes. Yes. this can be slow.
-START DB(--) SPACE(--) ACCESS(UT)
Then Recover tablespace LOGONLY (to current or TORBA or TOLOGPOINT)
Then Rebuild index as needed
-START DB(--) SPACE(--) ACCESS(RW)
This was already in use for lots of other mainframe stuff when I arrived here 8 years ago. The assumption was that it could work for DB2 also. There are design pieces in DB2 from the beginning that make this possible. Bottom line: backup is much faster, recovery requires a lot more work and time. Since we run few recoveries, it works for us. We run the copy utility rarely, mostly after (or concurrent with) reorg and load replace.
Do you think this is just for the lunatic fringe? Consider the SYSTEM BACKUP and RECOVER utilities in DB2v8, aimed mostly at the ERP crowd. They rely on flash copy or variations from vendors other than IBM. Jim Teng has new wrinkles in DB2v9 to allow recovery of individual objects. I suspect that dasd backups will eventually replace individual copy files for many people. I make no prediction about when. It does require a lot of coordination between dasd managers and DBAs.

Mark McCormack



The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at www.idug.org under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more.
If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services


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The IDUG DB2-L Listserv is only part of your membership in IDUG. DB2-L list archives, the FAQ, and delivery preferences are at http://www.idug.org/lsidug under the Listserv tab. While at the site, you can also access the IDUG Online Learning Center, Tech Library and Code Place, see the latest IDUG conference information, and much more. If you have not yet signed up for Basic Membership in IDUG, available at no cost, click on Member Services at http://www.idug.org/lsms