I agree with the DSU suggestion -- this is exactly the reason we use
that method with an Informix DB here.  Waiting for tape to do these
backups just isn't fast enough.  The DSU solves this problem completely.

-----Original Message-----
From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf Of Justin
Piszcz
Sent: Friday, March 27, 2009 4:48 PM
To: Larry Mascarenhas
Cc: veritas-bu AT mailman.eng.auburn DOT edu
Subject: Re: [Veritas-bu] Slow Informix Logs backups



On Fri, 27 Mar 2009, Larry Mascarenhas wrote:

> Hello,
>
> I'm running backups on Informix7 DBs. We're able to stream the DB
> backups using parallelism 4 and get good throughput (100MB/s, yes
> megabytes/sec, it is a SAN Media Server). A 300Gig DB takes less than
1
> hour.
>
> However (I know ;)), when it backs up the LOGS (all backups go to
tape,
> I don't have Disk backups), each log comes in as a separate request.
> Each log is therefore a separate job. So the time taken to process
this
> request is greater than the time to backup each log. ie each log is
> 100MB and the time taken is <2secs (when the resource is allocted and
> ready), but it takes 1+min to create the job/assign the resource/and
> begin writing. This is resulting in my never being able to catch up
with
> the rate of logs generation although the amount to be backed up is
> minimal eg 30logs is just 3Gig, but takes approx 30mins and by that
time
> 10 more logs are created. I am using media_unmount_delay so the tapes
> are not re-mounting for every request.
>
> I cannot increase the size of the LOGS as this would affect
replication
> and recoverability (double whammy). This is Symantec's recommendation.
>
> I'm looking for experiences that people have had to speed up the
> Informix backups.
>
> Thanks.
>
> -- 
>
> Larry Mascarenhas
> LMascare AT comcast DOT net
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>

Why not use a Disk Staging Unit if the logs are small enough?

Send to disk first -----> then shoot to tape?

Justin.
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