Thanks. That's exactly what I was looking for !!
A little late for today, since the backup actually aborted, but we can do
tomorrow. :-))
----- Original Message -----
Subject: Re: help with slow archive please
Date: Wed, May 21, 2008 10:41
From: "Tilman Model-Bosch" <tilleul17@[EMAIL PROTECTED]
>
Floyd Wellershaus wrote:
> > we have had some network issues.
> > The sars don't look different or excessive.
> > We are doing a full archive every night, and the database hasn't grown
> > much since last week, so that's not it.
> >
> > I am trying to be able to intrpret the onstat -g stq so that I can
> > hopefully see if the tape drive may be the bottleneck or the server
end.
> >
> > Thanks,
> > floyd
>
> Haven't done it in a while (no backup performance problems to
> interprete) but If I recall it correctly:
>
> full queue is where arcbackup1 has put data to get backed up . Empty
> queue is where there are backup buffers for arcbackup1 to get grabbed
> for additional pages.
>
> So if you see almost always buffers in full queue (and waiters on empty
> queue) I'd assume that the storage manager (or XBSA interface) does not
> grab the data quick enough for IDS. --> search for problems downstream
> of onbar (i.e. , network , storage manager, tape library...).
> If it is almost always empty queue which has all the buffers, arcbackup1
> does not deliver fast enough. --> IDS or chunk disk subsystem not fast
> enough.
> If it is the later case, check read performance on all the chunks.
>
> Here is a little UNIX command to help you doing a dd on all chunks.
> It dumps the dd commands to a file called ddfile , assumes 2k pages size
> and you need to replace <chunk> with something that greps all and only
> your chnks in the onstat -d output.
> (If you have other page sizes adjust bs, and the factor to calculate
> count and skip in the awk command)
> NB! There are probably better and more sophisticated ways out there ,
> but its a quick way to *****s disk speed for IDS.
> !Disclaimer: AS-IS, no warranty, no liablibilty , not tested
> extensively! )
>
> onstat -d | grep <chunk> | tr -s ' ' | cut -f 4,5,6,8 -d' ' | awk
> '{skip=$1/2; count=($2-$3)/2; printf "dd if="$4" of=/dev/null bs=2k
> skip=%d count=%d",skip, count ; print ""}' >ddfile
>
>
> HTH
> Tilman
>
>
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