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

From: Fmhabash <>
Date: Sat, 16 May 2009 18:27:33 -0400
Message-ID: <>

Just to pust some numbers here...
If you produce an awr comparison report between a good and a bad period, how are these numbers looking... - average read ms
- physical reads / sec

Throughout my experience with IO related issues, my most effective forensic evidence was these 2 stats on the db end. As DBA's we were asked to produce these stats after which sys/storage admins had to explain. Im my last engagement, we produced awr trend reports showing up 650ms read times on undo and temp tablespaces. In this particular instance, db was migrated to a new storage subsystem.  

Thank You.

-----Original Message-----
From: Rajeev Prabhakar <> Sent: Saturday, May 16, 2009 2:50 PM
To: Paweł Kotlarz <>
Cc: <> Subject: Re: Oracle 10g hangs intermittently waiting for I/O

Hi Pawel,

In no particular order, please check with your sysadmins/storage admins about the following :

  1. Queue depth of the LUNs / associated optimal settings for your storage.
  2. Any unsuccessful microcode/firmware upgrade on the FC fabric.
  3. Double check for any combination of any FC/non-FC drives OR any failure of drives/associated raid group rebuild errors.
  4. LUN level i/o statistics and any out of ordinary observations.


2009/5/16 Paweł Kotlarz <>:
> Thanks, Rajeev. I appreciate your help very much!
> Pawel


Received on Sat May 16 2009 - 17:27:33 CDT

Original text of this message