Re: Oracle 10g hangs intermittently waiting for I/O

From: Pawe³ Kotlarz <>
Date: Fri, 15 May 2009 21:02:26 +0200
Message-ID: <>

I will try it adding iflag=direct to bypass the Linux cache.



On 2009-05-15 17:41, Matthew Zito wrote:
> Ok, well, then, we'll move to plan B. Do a test like this while everything is working fine:
> [root_at_rh45-rac001-01 disks]# time dd if=/dev/oracleasm/disks/BAR of=/tmp/dd.out bs=1024k count=10
> 10+0 records in
> 10+0 records out
> real 0m0.911s
> user 0m0.002s
> sys 0m0.146s
> [root_at_rh45-rac001-01 disks]#
> That'll tell you roughly how fast you should expect to be able to read 10MB off of one of those disks. Do this a few times for the various disks that you think you might have problems with.
> Then, when you're having the problems, do the same test. If the dd takes dramatically longer to run, or hangs altogether, then you know it's an OS/storage issue. If everything hums along just as before, then it's probably an Oracle issue.
> Thanks,
> Matt

Received on Fri May 15 2009 - 14:02:26 CDT

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