Brconnect with dbverify on database with more than 1TB

[Former Member]

Hi,

today I work one a problem with brconnect and dbverify.

The time to finish the work one my db is > 48 hours and not acceptable.

My question is how can minimize the time of thes action, so that the check give me the right information in a acceptable time.

Option for more cpu don't solv my problem.

Thx in Advance.

Joe

[JPReyes]

You can use parallel processing to improve the performance of the brconnect command...

As far as I remember the swith is -p "X" where X is the number of threads to use...

Read SAP Note 403713.

Also, i found a reference here in the link above (even tho they're talking of update statistics it applies to any brconnect activity)

http://help.sap.com/saphelp_nw70/helpdata/en/df/01313bdffef106e10000000a11402f/frameset.htm

Regards

Juan

[Former Member]

Hi,

thx.

The -p options solv not my problem.

I've try it, but ( 8Processors machine, with 64GB RAM). I used 4 Threads, but the time is not under 40 hours and the Performance on the Box is negativ too.

Any other Idea?

Thx

Joe

[Former Member]

Hi,

Be patient ? You cannot go faster than music ! Reading more than 1 TB of data takes some time.

Maybe you can check your IO configuration ?

Regards,

Olivier

[JPReyes]

Hi Joe,

As far as i know theres no other way (beside parallel processing) to speed up the dbverify... as mentioned by Olivier check you hardware settings...

Regards

Juan

[Former Member]

Hi there

How do you backup this database? How long do these backups run? I suspect you are running your verify with brbackup -verify only_dbv, is this correct?

Olivier is correct, the verify certainly takes its time, but on the other hand on a decent system you should get something like 40mb/s. This means a terra byte database will be verified in 1000000mb / 40mb/s ~ 7hrs.

What kind of disk do you have, are they 100% busy during the verify run?

Regards

Michael

[Former Member]

Hi Michael,

we backup the database with ADSM LANFREE. These takes 4-5 hours. (without LANFREE Options > 20 hours.

Our Storage system is an IBM SAN Box.

brconnect with -all -cascade -p 3 (8 Pro. into a box) needs 48 hours the finish the work.

We've 7*24 hours the system up and, round about 1000 users online. (nighly a lot of Batch running on the System)

(4 Appl. Server, one DB Server).

I try to verfify the database mit brbackup .... so the test is finish after 30 hours. not so bad, but not really good...

Next I'll try to check parts of db (like BTABD, eq.) per day.

Thx to all

[Former Member]

Oh ok, i was wrong then. You do the validate structure thing. This is definitely a problem on larger databases. We do have single tables (+100gb / +1mio rows / +4 indexes) where a validate structure cascade runs for days.

As far as i know it is not possible to constantly (weekly) verify your db in most cases. A part from the runtime, the validate structure puts heavy load on your system. You might instead do:

- only validate structure the most important data regularly (-> system tablespace)

- only validate structure, when there is increased probability of corruption

- take a snapshot of the disks and verify there, or use a standby database (this will not guarantee your primary is not corrupt, but you will have a clean copy of your data)

- it is also possible to verify (dbv) with brbackup, this could be done during backups, or with rman

Regards Michael