KAIO error or warning

IDS 11.5FC6 on RHEL 5.2. We're getting a warning, or maybe error, each time we start one of the many instances on this server. requested number of KAIO events (16384) exceeds limit (8448). using 8448. Although the "limit" number varies; sometimes as low as 128. Any ideas what this is or if it's a worry? IBM Service Request Number 81212 019 866 refers. thanks

Neil, I would not worry too much but you should check the following two kernel parameters: "/proc/sys/fs/aio-max-nr" "/proc/sys/fs/aio-nr" Ids would like to use half of remaining system wide AIO requests... and not getting it Do you have other IDS instances running on the same machine or different SW using also the AIO interface ? Kind regards Sandor ------------------------------------------------------------------------------------------------------------------------------------------- IBM Deutschland Research & Development GmbH / Vorsitzender des Aufsichtsrats: Martin Jetter Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294 "Neil Truby" <neil.truby@arden ta.com> To Sent by: informix-list@iiug.org informix-list-bou cc nces@iiug.org Subject KAIO error or warning 01/21/2010 01:52 AM IDS 11.5FC6 on RHEL 5.2. We're getting a warning, or maybe error, each time we start one of the many instances on this server. requested number of KAIO events (16384) exceeds limit (8448). using 8448. Although the "limit" number varies; sometimes as low as 128. Any ideas what this is or if it's a worry? IBM Service Request Number 81212 019 866 refers. thanks _______________________________________________ Informix-list mailing list Informix-list@iiug.org http://www.iiug.org/mailman/listinfo/informix-list

http://www.ibm.com/developerworks/data/library/techarticle/dm-0503szabo/ When you start the first instance on the server it takes half of what is setup on the os. Each instance after that will also try and take half of the max the OS has defined. For each instance set KAIOON to the number of KAIO queues for each, rather than letting Informix take half. Thanks Roy On Jan 20, 7:52 pm, "Neil Truby" <neil.tr...@ardenta.com> wrote: > IDS 11.5FC6 on RHEL 5.2. > > We're getting a warning, or maybe error, each time we start one of the many > instances on this server. > > requested number of KAIO events (16384) exceeds limit (8448). using 8448. > > Although the "limit" number varies; sometimes as low as 128. > > Any ideas what this is or if it's a worry? > > IBM Service Request Number 81212 019 866 refers. > > thanks

"Sandor Szabo" <sandor.szabo@de.ibm.com> wrote in message news:mailman.480.1264063411.6236.informix-list@iiug.org... Neil, I would not worry too much but you should check the following two kernel parameters: "/proc/sys/fs/aio-max-nr" "/proc/sys/fs/aio-nr" >> Ids would like to use half of remaining system wide AIO requests... and not getting it Do you have other IDS instances running on the same machine or different SW >using also the AIO interface ? If I look at what it was: cat /proc/sys/fs/aio-max-nr 65536 Then increase it twenty-fold: echo 1280000 > /proc/sys/fs/aio-max-nr First instance OK Second instance 10:46:27 IBM Informix Dynamic Server Version 11.50.FC6 Software SerialNumber AAA#B000000 10:46:28 requested number of KAIO events (320000) exceeds limit (160000).using 160000. 10:46:29 IBM Informix Dynamic Server Initialized -- Shared MemoryInitialized. Third instance 10:47:57 requested number of KAIO events (320000) exceeds limit (40000).using 40000. 10:47:58 Physical Recovery Complete: 0 Pages Examined, 0 Pages Restored.Fourth instance 10:49:36 Physical Recovery Started at Page (2:2775). 10:49:36 requested number of KAIO events (320000) exceeds limit (10000).using 10000. 10:49:37 Physical Recovery Complete: 0 Pages Examined, 0 Pages Restored. etc. I can't see a pattern to this that will tell me what would be a suitable setting.

You can control how much KAIO resource each instance requests with the KAIOON environment variable. If you set: export KAIOON=20000 then that instance will only request 20000 concurrent IO blocks from the OS. With the default, 65535, the first server would have requested 32767, so if you want each server to get that many KAIO blocks, set KAIOON to 32767 and set aio_max_ar to 32767 * 2 * <# instances> or greater. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) IIUG Board of Directors (art@iiug.org) See you at the 2010 IIUG Informix Conference April 25-28, 2010 Overland Park (Kansas City), KS www.iiug.org/conf Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. 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, Jan 21, 2010 at 12:10 PM, Neil Truby <neil.truby@ardenta.com> wrote: > > "Sandor Szabo" <sandor.szabo@de.ibm.com> wrote in message > news:mailman.480.1264063411.6236.informix-list@iiug.org... > Neil, > I would not worry too much but you should check the following two kernel > parameters: > > "/proc/sys/fs/aio-max-nr" > "/proc/sys/fs/aio-nr" > > >> Ids would like to use half of remaining system wide AIO requests... and > not getting it > Do you have other IDS instances running on the same machine or different SW > >using also the AIO interface ? > > > If I look at what it was: > cat /proc/sys/fs/aio-max-nr > 65536 > > Then increase it twenty-fold: > echo 1280000 > /proc/sys/fs/aio-max-nr > > First instance > OK > Second instance > 10:46:27 IBM Informix Dynamic Server Version 11.50.FC6 Software Serial> Number AAA#B000000 > 10:46:28 requested number of KAIO events (320000) exceeds limit (160000).> using 160000. > 10:46:29 IBM Informix Dynamic Server Initialized -- Shared Memory> Initialized. > Third instance > 10:47:57 requested number of KAIO events (320000) exceeds limit (40000).> using 40000. > 10:47:58 Physical Recovery Complete: 0 Pages Examined, 0 Pages Restored.> Fourth instance > 10:49:36 Physical Recovery Started at Page (2:2775). > 10:49:36 requested number of KAIO events (320000) exceeds limit (10000).> using 10000. > 10:49:37 Physical Recovery Complete: 0 Pages Examined, 0 Pages Restored.> > etc. > > I can't see a pattern to this that will tell me what would be a suitable > setting. > > _______________________________________________ > Informix-list mailing list > Informix-list@iiug.org > http://www.iiug.org/mailman/listinfo/informix-list >