Verification after Data migration using Recovery Expert

Bharath Nunepalli

Verification after Data migration using Recovery Expert

Hi All,

We use Redirected Recovery of Recovery Expert to migrate data from one database to another database (within same sub-system or cross sub-systems).
As of now, there is no simple way of knowing whether complete data got migrated properly from source to target or not. And, this is a big concern for us.

I came up with a SQL query that compares source TS's COPYPAGESF (from SYSCOPY) with target TS's NACTIVE (from SYSTABLESPACESTATS) after data migration is done.
Most of the Tablespaces got same values, except for few (unable to figure out why).

E.g., TS1 got these values.
a. COPYPAGESF=5 and NPAGESF=66 (both from source TS’s SYSCOPY)
b. NACTIVE=35 and NPAGES=1 (both from target TS’s SYSTABLESPACESTATS after data migration is done)

Can anyone please help me in understanding why COPYPAGESF and NACTIVE values are different?

 

Bharath Nunepalli,

Senior DB2 DBA.

Jørn Thyssen

RE: Verification after Data migration using Recovery Expert
(in response to Bharath Nunepalli)

Hi Bharath,

The Redirected Recovery feature of Db2 Recovery Expert does not set the RTS when doing the recovery, so the values from SYSTABLESPACESTATS are not correct. You would need to do a REORG to get those updated (use KEEPDICTIONARY to avoid differences due to a new compression dictionary). BTW, this is the same behaviour as DSN1COPY. 

What is the concern? Do you want to run the verification one time only to convince yourself that the product is doing as promised? Or should the verification be run after every redirected recovery to "prove" that the right amount of data was recovered? 

How accurate should the comparison be? 

 

FYI: PI86756 which introduces an option to copy RTS and RUNSTATS from the source to the target (with some restrictions). This will obviously not help you to detect any discrepancies :) 

 

 

 

Best regards,

Jørn Thyssen

Rocket Software
77 Fourth Avenue • Waltham, MA • 02451 • USA
E: [login to unmask email] • W: www.rocketsoftware.com 

Views are personal. 

Bharath Nunepalli

RE: Verification after Data migration using Recovery Expert
(in response to Jørn Thyssen)

Data is not getting copied properly sometimes.

I need to do the verification after every redirected recovery to "prove" that the right amount of data was recovered.

Jørn Thyssen

RE: Verification after Data migration using Recovery Expert
(in response to Bharath Nunepalli)

Hi Bharath,

I was just reading through your PMR. I understand the problem now, and hope my colleagues can help you out.

Can you search through the output from the job for the ARYxxxxE message causing the missing data, e.g, using the REXX SDSF API? This will be a lot faster than running various counts, unloads, etc.

Best regards,

Jørn Thyssen

Rocket Software
77 Fourth Avenue • Waltham, MA • 02451 • USA
E: [login to unmask email] • W: www.rocketsoftware.com 

Views are personal.