Re: BRMS nightly save time differences

[Jim Oberholtzer <midrangel@xxxxxxxxxxxxxxxxx>]

Paul:

I think the key phrase was "we do append".  I'm guessing that the tape
transit time to search for the next available sequence number is largely
the difference.  I'd try to put an exit in the daily control group with a
"starting now" and "ending now" just before/after the *ALLUSR.  Then
compare that time to the weekly.  Assuming they are about the same, then
the difference is seek time on the tape.  LTO seek time is abysmal, so it
would not surprise me to find this out.

On Thu, Aug 27, 2015 at 9:46 AM, Steinmetz, Paul <PSteinmetz@xxxxxxxxxx>
wrote:

> On our Production LPAR, every night at 22:00, I run a full BRMS save SWA.
>
> Cause . . . . . :   Command to execute is: STRBKUBRM CTLGRP(SAVFULL05)
>   SBMJOB(*NO) APPEND(*YES) ACTIVITY(*CTLGRPATR) RETENTION(*DAYS 45).
>
> BRM16A1    Diagnostic              40   08/27/15  00:22:55.539417
> Q1AC0SLIB    QBRM        *STMT    Q1ARBK      QBRM        *STMT
> Message . . . . :   Backup *ALLUSR, type *FULL completed with errors.
> for sequence 57372,
>
> Once a week, same time, we run a different job using the same control
> group with different retention overrides and move policies.
>
> Cause . . . . . :   Command to execute is: STRBKUBRM CTLGRP(SAVFULL05)
>   SBMJOB(*NO) APPEND(*YES) ACTIVITY(*CTLGRPATR) RETENTION(*DAYS 396)
>   MOVPCY(CYCBRC396).
>
> BRM16A1    Diagnostic              40   08/25/15  00:10:34.356003
> Q1AC0SLIB    QBRM        *STMT    Q1ARBK      QBRM        *STMT
> Message . . . . :   Backup *ALLUSR, type *FULL completed with errors.
> sequence 18100
>
> The once a week *ALLUSR part of the save is consistently 10 to 15 minutes
> faster than the daily save.
> During the backup window, no batch jobs, only a handful of interactive
> users.
>
> Why would a retention override result in a performance improvement during
> the *ALLUSR?
> *ALLDLO and *LINK times are the same.
> We do append, sequence numbers are higher for the nightly save compared to
> the weekly save.
>
> Thank You
> _____
> Paul Steinmetz
> IBM i Systems Administrator
>
> Pencor Services, Inc.
> 462 Delaware Ave
> Palmerton Pa 18071
>
> 610-826-9117 work
> 610-826-9188 fax
> 610-349-0913 cell
> 610-377-6012 home
>
> psteinmetz@xxxxxxxxxx
> http://www.pencor.com/
>
>
>
>
>
>
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