IDS Forum

Re: directing onbar to disk?

Posted By: Martin Fuerderer
Date: Tuesday, 13 November 2007, at 4:43 a.m.

In Response To: directing onbar to disk? (GARY PRICE)

Hi,

having read other responses I try to complement the info a bit:

ON-Bar will work only with a storage manager (SM), regardless
whether the objects to back up are logs or dbspaces. Without
the SM, ON-Bar will not be able to backup anything. This is
because ON-Bar uses the XBSA only and there is no other
way for ON-Bar to put the backup data anywhere else. I.e.
there is no way to configure ON-Bar to write something to disk
instead of sending the data to the SM via XBSA.

If the SM is unavailable for some time during the day, then
during that time backup with ON-Bar will not work. As you
already experienced this means that logs will fill but not be
backed up.

The best solution to this problem (I think) is to have enough
log space (sum of the size of all logical log files), so that
you do not get into a "logs full" situation when logs cannot
be backed up. That probably means that you have to add
more (and possibly bigger) log files, so that operations can
continue without "log full" during the SM outage - including
the time it will take after the SM outage to catch up with
backing up all the logs that filled in the meantime.

The day time of the SM outage (11:00 - 13:00) may of course
be unlucky - probably it is the least busy time for general
backup tasks, but may well be the most busy time for
transactions filling the logs. :-(
Maybe it is possible to negotiate a different time window for
this daily SM outage and thus to alleviate the problem
somewhat?

I would not recommend any other schemes to solve this
problem as they will add significantly to the complexity of
the restore procedure, which should be kept ASAP
[ As Simple As Possible ;) ] because restore usually is a
stressful situation and thus prone to user errors.

[ Example schemes that I do not recommend include:

- doing log backup using ontape instead of onbar.

This involves complicated handling of log backup files

during backup and restore and makes selection of valid

backup during restore difficult (for ON-Bar) ...

- Using a different SM for log backup (i.e. different from SM

used for dbspace backup). E.g. ISM is local and independent

of Netbackup availability, but this would require very

complicated restore procedures with switching SM between

physical and logical restore ... ]

With IDS 11 you could use "ontape" to backup everything
(dbspaces and logs) to directly disk without complicated backup
file handling. But then "ontape" still does not offer parallel
operation for dbspace backup.

Regards,
Martin
--
Martin Fuerderer
IBM Informix Development Munich, Germany
Information Management

IBM Deutschland GmbH
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Board of Management: Martin Jetter (Chairman), Rudolf Bauer, Christian
Diedrich, Christoph Grandpierre, Matthias Hartmann, Thomas Fell, Michael
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ids-bounces@iiug.org wrote on 12.11.2007 22:09:02:

> I'm migrating an Informix enviroment to the datacenter of our parent
company.
> They use Netbackup as the storage mgr (we use TSM). The Netbackup agent
for
> Informix is installed and onbar configured to use it. Netbackup is taken
down
> everyday from 1100-1300 for 'maintenance'. This, of course, causes any
log
> backup to fail; if there is a batch job running, the logs will fill.
>
> Due to the above, I'd like to be able to direct onbar to write to disk
first
> and let Netbackup take care of getting it off to tape later. We do this
with
> TSM, using a 100GB disk pool. Our Oracle databases have a parameter
> (LOG_ARCHIVE_DEST) which allows you to specify a disk location for log
> offloads. I've not found anything in the Informix doc. that would allow
this
> to be done using Onbar (maybe I've missed something?).
>
> Any help, as always, would be appreciated.
>
> Informix 9.40FC3
> AIX 5.x
>
>
>
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> Forum Note: Use "Reply" to post a response in the discussion forum.

Messages In This Thread

• directing onbar to disk?
  GARY PRICE -- Monday, 12 November 2007, at 4:09 p.m.
  • Re: directing onbar to disk?
    Dominic Seah Chin Teck -- Monday, 12 November 2007, at 8:46 p.m.
  • Re: directing onbar to disk?
    Martin Fuerderer -- Tuesday, 13 November 2007, at 4:43 a.m.
    • Re: directing onbar to disk?
      Chris Bandy -- Tuesday, 13 November 2007, at 5:02 a.m.

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