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How do we get Commvault to do our Sybase ASE backups correctly (truncate_only on logs)

Hi

We're having some difficulties setting up Commvault for our Sybase ASE SAP systems. The difficulties are to do with the fact there's multiple databases to backup, and the transaction log backups that go with them - or in some cases, the 'truncate_only' option that's required.

I.e. here's some we need to backup:

dump database SDP using config = 'SDPDB'
dump database master using config = 'SDPDB'
dump database saptools using config = 'SDPDB'

etc..

trans logs:

dump transaction SDP using config = 'SDPLOG'
dump transaction master using config = 'SDPLOG' with truncate_only

Note that there's no trans logs for saptools, and that there's no backup of the trans logs for master as such - it's a "truncate_only". This is supposed to be ran immediately after the master backup. However, when you try and set up backups in Commvault, you have to tick/untick the transaction log 'do not truncate log' option (as per http://documentation.commvault.com/commvault/v10/article?p=products/sybase/backup_adv.htm *) for the whole backup set.

So really we'd need to create a couple of backup sets, one for SDP and any others that need a trans log backup, and another for those that need truncating, such as master - right?

However, Commvault won't let us do that. It wants to add in all of the databases, not just one or a selection. The interface isn't 'friendly' or intuitive; we found we had to keep going back between screens, and at one point, we'd managed to add in a selection of the databases we wanted to do a truncate on (i.e., master, model, sybmgmtdb, sybsystemdb, sybsystemprocs) but when we saved it, came out and came back in, it had added the rest (SDP, saptools etc). That's pretty dangerous - we don't want to do a truncate on our SDP (main SAP DB) trans logs!

Also having two different set isn't ideal, the truncate is supposed to be done at the same time/immediately after. Is there any way to group this?

The only option we thought of was calling our backup script (which contains the correct sequences of backups, trans logs backups and truncates) directly from CommVault; not sure we can do this (?) and even if we could, it would just backup to disk/whatevers in our script config and not to CommVault.

Any thoughts/suggestions? I think one of the main problems here is that there's very few people using CommVault with SAP on Sysbase ASE...

Thanks
Ross

P.S. *Going back to the document, does the following sentence make any sense to anyone?
It doesn't seem to be correct nor make any sense to me:

"Back Up Transaction Log of Damaged Database (Do Not Truncate Logs)
In Sybase server, some databases may not have log devices. By default, when you perform a log backup, the system performs log backups of those databases that possess transaction logs. Hence, it is necessary to perform a full backup after a log backup. A full backup will perform a backup of all databases irrespective of the fact that they may or may not possess transaction logs."

I'm not even sure this is how you do the "truncate_only" option, from that wording! Do Commvault actually understand how ASE works?

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3 Answers

  • May 11, 2017 at 01:01 PM

    Hi Ross,

    I don't have any direct experience with Commvault. However, my impression from the documentation you point to is that this "do not truncate log" checkbox option would be to invoke the "dump tran with no_truncate" option. This option is very rarely used, it is for cases where you have the data and log segments on different devices and experience a failure of a data device; the option allows you to dump the log records from the log devices even if the system tables aren't available due to the bad data device. This also ties in with your "p.s." question, the section header there is definitely talking about the case where there is a damaged device. I don't think you should be checking this box.

    A normal dump tran command both copies the log records to an archive device and truncates the inactive part of the log (from the beginning of the log to the start of the oldest open transaction).

    It sounds like Commvault is expecting that data and log segments/devices will be separated (as they must be) for database that "dump tran to archive" will be done for, and if data and log is mixed it either does nothing (expecting you to use the trunc log on ckpt database option) or does a dump tran with truncate_only. It sounds like the full backup option does a full dump database on all databases (which matches your experience of databases being automatically added to the dump set).

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    • Thanks Bret, that's awesome! Enabled monitoring and managed to capture this during the full online master backup (no trans logs) from CommVault:

      use master
      select segmap, lstart, vstart, size,vdevno from sysdatabases db, sysusages u where db.dbid = u.dbid and db.name = "TDD"
      select low, high,vdevno, status, cntrltype, name, phyname from sysdevices where vdevno = 11 and cntrltype = 0
      select low, high,vdevno, status, cntrltype, name, phyname from sysdevices where vdevno = 5 and cntrltype = 0
      select low, high,vdevno, status, cntrltype, name, phyname from sysdevices where vdevno = 5 and cntrltype = 0
      dump database master to "SybGalaxy:: -file /simpana/simpana/Base/Temp//sybGalaxyParams844792_0"
      stripe on"SybGalaxy:: -file /simpana/simpana/Base/Temp//sybGalaxyParams844792_1"
      stripe on"SybGalaxy:: -file /simpana/simpana/Base/Temp//sybGalaxyParams844 792_2"
      stripe on"SybGalaxy:: -file /simpana/simpana/Base/Temp//sybGalaxyParams844792_3" with blocksize=1048576
      dump transaction master with truncate_only

      I.e. it DOES do a truncate_only as part of the full backup!

      Good to know :)

      Many thanks for your help with all this, feel I'm starting to understand ASE a (little) bit more now!

  • May 11, 2017 at 03:50 PM

    Hello Ross,

    As far I know

    Option : 1

    You need CommVault agent for Sybase database (If CommVault have it!!) If that agent installed on DB server and you taking backup it will truncate logs automatically after successful log backups

    Option : 2

    If this option is not available please backup DB and log through Sybase scripts at file system and take backup of those DB and log dumps through CommVault.

    Note: if you go option 2 make sure you cleanup filesystem regularly.

    Regards,

    Yogesh

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  • Jun 08, 2017 at 09:13 AM

    As per exchange with Bret, the answer is:

    You set up CommVault to backup ALL the databases, and create two schedules: one to do a full online backup of them, and one to do a transaction logs of them.

    CommVault 'knows' which DBs have trans logs.

    The full online backup handles the necessary 'truncate_only' of master (not done as part of the trans log backups) (as well as model & saptempdb).

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