I think you've entered the realm of difficult problems 8~) (Dealing with extreme cases). Judging from the little concrete responses, you may be an expert on this than anyone on the list. Increasing i/o polling count might work. If it doesn't work then here is my reasoning:
From what I gather, increasing that value is like trying to find a balance between processor time and disk i/o time. A process that has a lot of disk i/o leaves the processor idle so the processor might as well work on another process HOWEVER that other process should not be disk i/o intensive but should be processor intensive. HOWEVER (again) a lot of disk i/o processes can be run if there is no bottleneck on disk i/o (thus increasing the throughput of disk i/o processes) and this might be the case if the i/o load is spread over several disks AND THIS IS THE REASON I DON'T THINK increasing the polling count will work for your case i.e. the problem is that your disk i/o is contrained, allowing more disk i/o processes to run doesn't remove the problem. THEREFORE if most of the processes in your case are disk i/o intensive, increasing the polling count might not work. BUT BY ALL MEANS GIVE IT A TRY and let us know if it works.
8~) --- On Wed, 6/2/10, wambugu esther <essiekui@gmail.com> wrote: From: wambugu esther <essiekui@gmail.com> Subject: Re: [Skunkworks] SYBASE ERROR To: "Skunkworks Mailing List" <skunkworks@lists.my.co.ke> Date: Wednesday, June 2, 2010, 2:40 PM On Wed, Jun 2, 2010 at 2:38 PM, wambugu esther <essiekui@gmail.com> wrote: Thanks, thought i would contain it by increasing a parameter called i/o polling count and time slice to ensure that alot of i/o processing is not happening often such as applications to take alittle longer in the processor than having alot of i/o being done. What do u think Regards Esther On Wed, Jun 2, 2010 at 2:16 PM, wesley kirinya <kiriinya2000@yahoo.com> wrote: Never used it, however: Increase the I/O throughput or find a way to reduce the I/O and if you can't implement a limit to the allowed I/O, spread the I/O load to other disks. Using disks with faster I/O may also help. You may not see hardware errors in OS log because it's not a real device failure but a device failure in the context of the DB. Check the generated stack trace. There could be valuable info there. --- On Wed, 6/2/10, wambugu esther <essiekui@gmail.com> wrote: From: wambugu esther <essiekui@gmail.com> Subject: Re: [Skunkworks] SYBASE ERROR To: "Skunkworks Mailing List" <skunkworks@lists.my.co.ke> Date: Wednesday, June 2, 2010, 11:27 AM Dear Rad, Im getting it if the server is doing alot of I/O last time i got it 5 times,when the server was tring to access a big and busy table.. On Wed, Jun 2, 2010 at 10:27 AM, Rad! <conradakunga@gmail.com> wrote:
How frequently do you get this error? You may get it when the server is doing a lot of IO
On Wed, Jun 2, 2010 at 10:10 AM, wambugu esther <essiekui@gmail.com> wrote:
thanks Rad, The product is ASE 12.5.4,Running on HP-UX 11.3 itanium.
kind regards Esther
On Wed, Jun 2, 2010 at 10:08 AM, Rad! <conradakunga@gmail.com> wrote:
Help people help you
1) Which Sybase Product? (ASA? ASE? IQ?) 2) Which version? 3) Which OS?
On Wed, Jun 2, 2010 at 10:04 AM, wambugu esther <essiekui@gmail.com> wrote:
hey guys..
im getting a sybase error error 694(An attempt was made to read logical page '%ld', virtpage '%ld' from virtual device '%d' for
object '%ld' in database '%d'. The page was not read successfully. You may have a device problem or an operating system problem.). The SYBASE write up talks about it being a hardware error but hardware
error logs don't show up any problem with the hardware. So was wondering if i increase the rate of I/O polling count which controls the maximum number of processes that Adaptive Server can run before the scheduler checks for disk and/or network I/O completions.
has anyone encountered the error and how did they sort it out...
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-- Best regards Esther Wambugu _______________________________________________ Skunkworks mailing list Skunkworks@lists.my.co.ke http://lists.my.co.ke/cgi-bin/mailman/listinfo/skunkworks ------------ Skunkworks Server donations spreadsheet http://spreadsheets.google.com/ccc?key=0AopdHkqSqKL-dHlQVTMxU1VBdU1BSWJxdy1f... ------------ Skunkworks Rules http://my.co.ke/phpbb/viewtopic.php?f=24&t=94 ------------ Other services @ http://my.co.ke _______________________________________________ Skunkworks mailing list Skunkworks@lists.my.co.ke http://lists.my.co.ke/cgi-bin/mailman/listinfo/skunkworks ------------ Skunkworks Server donations spreadsheet http://spreadsheets.google.com/ccc?key=0AopdHkqSqKL-dHlQVTMxU1VBdU1BSWJxdy1f... ------------ Skunkworks Rules http://my.co.ke/phpbb/viewtopic.php?f=24&t=94 ------------ Other services @ http://my.co.ke -- Best regards Esther Wambugu -- Best regards Esther Wambugu -----Inline Attachment Follows----- _______________________________________________ Skunkworks mailing list Skunkworks@lists.my.co.ke http://lists.my.co.ke/cgi-bin/mailman/listinfo/skunkworks ------------ Skunkworks Server donations spreadsheet http://spreadsheets.google.com/ccc?key=0AopdHkqSqKL-dHlQVTMxU1VBdU1BSWJxdy1f... ------------ Skunkworks Rules http://my.co.ke/phpbb/viewtopic.php?f=24&t=94 ------------ Other services @ http://my.co.ke