Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Rémy Beaumont
On 30-Aug-05, at 12:15, Tom Lane wrote: =?ISO-8859-1?Q?R=E9my_Beaumont?= [EMAIL PROTECTED] writes: The stats of the NetApp do confirm that it is sitting idle. Really? CPU NFS CIFS HTTP TotalNet kB/s Disk kB/s Tape kB/s Cache Cache CP CP Disk DAFS FCP iSCSI

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Michael Stone
On Mon, Aug 29, 2005 at 09:42:46AM -0400, Rémy Beaumont wrote: We have been trying to pinpoint what originally seem to be a I/O bottleneck but which now seems to be an issue with either Postgresql or RHES 3. Nope, it's an IO bottleneck. The behavior we see is that when running queries that

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Tom Lane
=?ISO-8859-1?Q?R=E9my_Beaumont?= [EMAIL PROTECTED] writes: The stats of the NetApp do confirm that it is sitting idle. Really? CPU NFS CIFS HTTP TotalNet kB/s Disk kB/s Tape kB/s Cache Cache CP CP Disk DAFS FCP iSCSI FCP kB/s in

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Tom Lane
=?ISO-8859-1?Q?R=E9my_Beaumont?= [EMAIL PROTECTED] writes: On 30-Aug-05, at 12:15, Tom Lane wrote: I know zip about NetApps, but doesn't the 8th column indicate pretty steady disk reads? Yes, but they are very low. Sure, but that's more or less what you'd expect if the thing is randomly

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Rémy Beaumont
On 30-Aug-05, at 12:29, Tom Lane wrote: =?ISO-8859-1?Q?R=E9my_Beaumont?= [EMAIL PROTECTED] writes: On 30-Aug-05, at 12:15, Tom Lane wrote: I know zip about NetApps, but doesn't the 8th column indicate pretty steady disk reads? Yes, but they are very low. Sure, but that's more or less

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Josh Berkus
Remy, The behavior we see is that when running queries that do random reads on disk, IOWAIT goes over 80% and actual disk IO falls to a crawl at a throughput bellow 3000kB/s (We usually average 4 kB/s to 8 kB/s on sequential read operations on the netapps) This seems pretty low for a

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Woody Woodring
Have you tried a different kernel? We run with a netapp over NFS without any issues, but we have seen high IO-wait on other Dell boxes (running and not running postgres) and RHES 3. We have replaced a Dell PowerEdge 350 running RH 7.3 with a PE750 with more memory running RHES3 and it be

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Rémy Beaumont
On 30-Aug-05, at 14:32, Josh Berkus wrote: Remy, The behavior we see is that when running queries that do random reads on disk, IOWAIT goes over 80% and actual disk IO falls to a crawl at a throughput bellow 3000kB/s (We usually average 4 kB/s to 8 kB/s on sequential read

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Rémy Beaumont
-performance@postgresql.org Subject: Re: [PERFORM] High load and iowait but no disk access   Have you tried a different kernel?  We run with a netapp over NFS without any issues, but we have seen high IO-wait on other Dell boxes (running  and not running postgres) and RHES 3.  We have replaced

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread Anjan Dave
? Thanks, Anjan From: Woody Woodring [mailto:[EMAIL PROTECTED] Sent: Tuesday, August 30, 2005 2:30 PM To: 'Rémy Beaumont'; pgsql-performance@postgresql.org Subject: Re: [PERFORM] High load and iowait but no disk access Have you tried a different kernel? We run with a netapp over NFS

Re: [PERFORM] High load and iowait but no disk access

2005-08-30 Thread mudfoot
] Sent: Tuesday, August 30, 2005 2:30 PM To: 'Rémy Beaumont'; pgsql-performance@postgresql.org Subject: Re: [PERFORM] High load and iowait but no disk access Have you tried a different kernel? We run with a netapp over NFS without any issues, but we have seen high IO-wait on other Dell