I think I can confirm this. I took my database volumes, and split them up into individual volumes. What I saw, was TSM hitting one volume, and it's mirror. It was much slower than the striped volumes. I now have it striped across 6 volumes, instead of only 4. I am also experimenting with making the storage pool volumes individual JFS files, instead of raw striped volumes. I have only converted one at this time, but it seems like read performance has gone way up. I did this also because the loss of one disk killed the whole storage pool, and while it is rare, it happened to us about 3 weeks ago, and I lost abou 120GB of data.
Andy Carlson |\ _,,,---,,_ [EMAIL PROTECTED] ZZZzz /,`.-'`' -. ;-;;,_ BJC Health System |,4- ) )-,_. ,\ ( `'-' St. Louis, Missouri '---''(_/--' `-'\_) Cat Pics: http://andyc.dyndns.org/animal.html On Mon, 12 Nov 2001, Joshua S. Bassi wrote: > I do not believe that TSM starts a separate thread for each DB volume > created. That is how disk stg pool volumes work, but not the DB. The > DB is read sequentially from what I understand. > > > -- > Joshua S. Bassi > Independent IT Consultant > IBM Certified - AIX/HACMP, SAN, Shark > Tivoli Certified Consultant- ADSM/TSM > Cell (408)&(831) 332-4006 > [EMAIL PROTECTED] > > -----Original Message----- > From: ADSM: Dist Stor Manager [mailto:[EMAIL PROTECTED]] On Behalf Of > Salak Juraj > Sent: Monday, November 12, 2001 2:06 AM > To: [EMAIL PROTECTED] > Subject: Re: Best Database Performance > > Hi, > > this has been discussed very often, you may ant to have a look into > forums history on http://msgs.adsm.org. > > Database performace is all about random access times, not about speed of > streaming. > > Basically, TSM will start one I/O in each database volume, > so having 4 database volumes spread over 4 physical disk may be a good > solutions. > > If your disk controller has sigificant amount of cache and good > optimising alghoritm, > enabling much more I/O on one disk could be helpfull. If you have almost > no cache on controller and on your disks, > this may slow down your DB significantly. > > There are few parameters in OPT file which affect the performance > (parallel write, read with verify), > there you can gain some speed at the costs of security. > > Do allow as much software disk cache as possible, it usually helps a > lot. > > Berst Regards > > Juraj �alak > Asamer Familienholding G M B H > EDV > Unterthalhamstra�e 2 > A-4694 Ohlsdorf > �sterreich > www.asamer.at > > B�ro: +43 7612 799 529 > Mobil: +43 664 528 6474 > e-mail: [EMAIL PROTECTED] > > > > > > > > -----Original Message----- > From: Andy Carlson [mailto:[EMAIL PROTECTED]] > Sent: Friday, November 09, 2001 4:16 PM > To: [EMAIL PROTECTED] > Subject: Best Database Performance > > > Does anyone have a feeling about what is best for database > performance? I have, since we moved to AIX, taken the 4 physical drives > (actually 8 with ADSM mirroring), and striped it into one large > volume. I saw a post the other day that suggested that maybe splitting > it to 4 individual volumes might be better, as ADSM can schedule across > these volumes. What I am seeing leads me to believe that ADSM is > hitting one volume, and it's mirror predominately. Was I better off > striped? Any suggestions? Thanks for any info. > > Andy Carlson |\ _,,,---,,_ > [EMAIL PROTECTED] ZZZzz /,`.-'`' -. ;-;;,_ > BJC Health System |,4- ) )-,_. ,\ ( `'-' > St. Louis, Missouri '---''(_/--' `-'\_) > Cat Pics: http://andyc.dyndns.org/animal.html >
