What version did you last see the problem?  I'm interested as I'm about
to put in a new TSM server, and I was contemplating which version to go
to.

See Ya'
Howard

> -----Original Message-----
> From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
> Of Matthew Glanville
> Sent: Monday, April 07, 2008 8:44 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: [ADSM-L] Improving TSM performance - memory related
> setting
> 
> Just a warning, don't necessarily go to 1/2 or 1/8th of your total
> physical memory..
> 
> If your server has 64 GB of memory, 8 GB (1/8th) for BUFPOOLSIZE is
> probably too high.  I would keep it below 1 GB unless you prove to
> yourself with some testing that it is helping speed up the backups or
> restores.  Just don't look at database cache hit rate.
> 
> I think there's some inefficiency in how TSM database cache works, as
> it
> may have to search through that cached memory to find a hit.  When you
> are
> caching 8 GB, that takes some time to search through all that.
> 
> You'll see this as the dsmserv processes CPU use will increase the
> larger
> the BUFPOOLSIZE is.  If it takes longer to search through that memory
> than
> it does to read the page from disk, you are hurting performance not
> helping it by caching in memory.
> 
> Maybe DB2 TSM in version 6 will help this issue.
> I tried to put a problem in for it a few years back, but couldn't get
> beyond level 2 since no one understood what I was talking about, they
> kept
> thinking the server was slow due to the operating system using it's
own
> page file to make up for the large memory setting, even though the 64
> bit
> server had 32 GB of physical memory...  Ahh well.  I can use that
other
> 30
> GB for something else.
> 
> or is it fixed now?
> Matt G.
> 
> 
> "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote on 04/04/2008
> 03:40:56 AM:
> 
> > Bufpoolsize should be set between 1/2 and 1/8 of the among of the
> > total physical memory, if I remember well, that is, what best
> > practices recommend.
> > Also if you modify this parameter you will have to take a look at
> > the percentage hit cache (q db f=d) that can be increase (modifying
> > the bufpolsize), or perhaps decrease if the setting is incorrect.
> > Percentage hit cache must be above 99 %.
> >
> > I will also recommend to take a look at the performance tuning
> > guide, that will let you know more about many settings that can
> > increase the performance of your TSM server.
> >
> > Regards,
> > Bernaldo.
> >
> >
> >
> > ----- Mensaje original ----
> > De: Paul Dudley <pdudley AT ANL.COM DOT AU>
> > Para: ADSM-L AT VM.MARIST DOT EDU
> > Enviado: viernes, 4 de abril, 2008 5:44:02
> > Asunto: Re: [ADSM-L] Improving TSM performance - memory related
> setting
> >
> > Currently the BUFPOOLSIZE is set to:
> >
> > BufPoolSize: 122,880 K
> >
> > The server has 3 Gb of memory. Is this something I can increase?
> >
> > Regards
> > Paul Dudley
> >
> > Senior IT Systems Administrator
> > ANL IT Operations Dept.
> > ANL Container Line
> > pdudley AT anl.com DOT au
> > 03-9257-0603
> > http://www.anl.com.au
> >
> >
> >
> > > -----Original Message-----
> > > From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On
> > > Behalf Of Skylar Thompson
> > > Sent: Friday, 4 April 2008 1:05 PM
> > > To: ADSM-L AT VM.MARIST DOT EDU
> > > Subject: Re: [ADSM-L] Improving TSM performance - memory related
> > setting
> > >
> > > Paul Dudley wrote:
> > > > If I recall correctly there is a TSM system setting that relates
> to
> > the
> > > > memory available on the server, and you can check and adjust
this
> > > > setting to improve performance of your TSM server.
> > > >
> > > >
> > > >
> > > > Can anyone remind me which setting it is?
> > > >
> > > >
> > >
> > > Are you thinking of BUFPOOLSIZE and LOGPOOLSIZE? The former
> controls
> > > the
> > > size of the database buffer pool (bounded only by the physical
> memory
> > of
> > > the machine), and the latter the size of the temporary transaction
> > space
> > > in the recovery log (up to 8192 pages IIRC).
> > >
> > > --
> > > -- Skylar Thompson (skylar2 AT u.washington DOT edu)
> > > -- Genome Sciences Department, System Administrator
> > > -- Foege Building S048, (206)-685-7354
> > > -- University of Washington School of Medicine