Re: Backup using only one CPU - SA wants to know why

From: mike boligan <mboligan_at_yahoo.com>
Date: Mon, 12 Nov 2012 13:10:59 -0800 (PST)
Message-ID: <1352754659.92690.YahooMailClassic_at_web113304.mail.gq1.yahoo.com>



I think this is multiprocessing vs multiprogramming http://publib.boulder.ibm.com/infocenter/tpfhelp/current/index.jsp?topic=%2Fcom.ibm.ztpf-ztpfdf.doc_put.cur%2Fgtpc3%2Fc32mul2.html

You (or RMAN I should say) are not multiprocessing not multiprogramming, not sure there is a parameter to flip for that, sounds more to me like how RMAN was written.

Mike

  • On Mon, 11/12/12, Sandra Becker <sbecker6925_at_gmail.com> wrote:

From: Sandra Becker <sbecker6925_at_gmail.com> Subject: Re: Backup using only one CPU - SA wants to know why To: Christopher.Taylor2_at_parallon.net
Cc: oracle-l_at_freelists.org
Date: Monday, November 12, 2012, 3:56 PM

I have a hunch it's something along those lines, but don't know how to prove it.  My SA insists there's a setting in the database to "turn on multiple CPUs".  If it already recognizes there are 5 of them, I'm not sure what else I can do.
Sandy

On Mon, Nov 12, 2012 at 1:53 PM, <Christopher.Taylor2_at_parallon.net> wrote:

> According to my AIX admin (on a similar question I asked him about active
> sessions) he said its because of the way IBM does CPU scheduling.
>
> I wish I had more info on that.
>
> Chris
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]
> On Behalf Of Sandra Becker
> Sent: Monday, November 12, 2012 1:39 PM
> To: oracle-l
> Subject: Backup using only one CPU - SA wants to know why
>
> Oracle 11.2.0.2
> SLES11 on IBM mainframe
> DB size - just below 1T
> I run an incremental 0 backup on my production OLTP once a week,
> incrementals the rest of the week.  Recently changed the disk_asynch_io to
> TRUE and the filesystemio_options to SETALL, per recommendations from
> Oracle.  I then added a channel to the backup scripts so it uses 4
> channels.  These changes shaved 35 pecent off the time it takes to run the
> incr0 backup, which I am very happy with.
>
> The SA monitoring the performance of the mainframe says the incremental 0
> backup of our production OLTP is pegging a single CPU, out of 5 available.
>  He thinks the backup would run even faster if it used more CPUs and
> suggested setting the PARALLELISM parameter to more than 1.  Unbeknownst to
> him, it had been set to 3 for the past 6 years.  He wants to know why the
> backup isn't using more CPUs.  Any ideas/suggestions?
>
> --
> Sandy
> Transzap, Inc.
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

-- 
Sandy
Transzap, Inc.


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Received on Mon Nov 12 2012 - 22:10:59 CET

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