IO problems and perf

Hi again :) I have some IO problems what cause probably the performance problems I had. So I'm running 11.5FC4, and only IDS on this server, and I've got 2 processors, here are some of my config params : DIRECT_IO 1 RESIDENT -1 USEOSTIME 1 I'll make a test by resetting RESIDENT and USEOSTIME params to 0. Thank you for your help

Regards, Mr. Ramseyer: We´re here with a similar ambient, except for the number of processors (our machine is a 4xdual-core = 8) and our o.s. is linux_64 (redhat based). I just optimized our BTSCANNER settings and also BUFFERPOOL, and since the installation of our engine, our IO´s still peaking sometimes, but in average is around 85% idle time of cpus. If you find out some other configs that could helps us, we can share the knowledge, ok? Tip: on the iiug site, had you read the conference´s manuals?? Thats an excelent starting point to performance upgrades! Regards. Alexandre Marini Analista de Tecnologia da Informação - DBA msn: alexandre_marini@hotmail.com SEFAZ-MS / UIMP / Sistemas: Fronteiras e SIG-DW JEAN-MICHEL RAMSEYER escreveu: > Hi again :) > > I have some IO problems what cause probably the performance problems I had. So > I'm running 11.5FC4, and only IDS on this server, and I've got 2 processors, > here are some of my config params : > DIRECT_IO 1 > RESIDENT -1 > USEOSTIME 1> > I'll make a test by resetting RESIDENT and USEOSTIME params to 0. > > Thank you for your help > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > > >

If nothing else is running on the box then RESIDENT is irrelevant. Setting RESIDENT to 1 prevents the 'resident' shared memory segment (which contains the buffer cache and header structures for controlling shared memory) from being swapped out by other processes - you can also set it to any positive number in which case that many shared memory segments will be locked in memory (so the resident segment and N-1 virtual segments) or to -1 to lock all shared memory segments. USEOSTIME is cheap to implement on modern OSes - obviously you should test that assertion yourself. DIRECT_IO is only used if your chunks are defined as COOKED devices or as filesystem COOKED files and the OS and filesystem support the O_DIRECT attribute for opening files. There's lots else you can and should tune to improve server performance. See the Performance Guide manual, the history of this forum and the CDI Newsgroup, and the conference presentations on the IIUG web site members' pages. Art S. Kagel Oninit (www.oninit.com) IIUG Board of Directors (art@iiug.org) Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Oninit, the IIUG, nor any other organization with which I am associated either explicitly or implicitly. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Thu, Jun 18, 2009 at 10:07 AM, JEAN-MICHEL RAMSEYER < jm.ramseyer@greenivory.com> wrote: > Hi again :) > > I have some IO problems what cause probably the performance problems I had. > So > I'm running 11.5FC4, and only IDS on this server, and I've got 2 > processors, > here are some of my config params : > DIRECT_IO 1 > RESIDENT -1 > USEOSTIME 1> > I'll make a test by resetting RESIDENT and USEOSTIME params to 0. > > Thank you for your help > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --001636c5a8d1950bfc046ca124d2