Re: Disk file operations I/O
From: Yong Huang <yong321_at_yahoo.com>
Date: Fri, 20 Jan 2012 08:34:43 -0800 (PST)
Message-ID: <1327077283.72156.YahooMailClassic_at_web181202.mail.ne1.yahoo.com>
> Jonathan pointed out that there is a bug with "Disk file operations
> I/O" with dNFS.
> The database isn't on dNFS but is using NFS
Date: Fri, 20 Jan 2012 08:34:43 -0800 (PST)
Message-ID: <1327077283.72156.YahooMailClassic_at_web181202.mail.ne1.yahoo.com>
> Jonathan pointed out that there is a bug with "Disk file operations
> I/O" with dNFS.
> The database isn't on dNFS but is using NFS
If you can capture the session waiting on the event, can you trace the shadow process to see what system call it's making? Is it open()? pstack on the process is helpful too.
The bug you referenced also has a description in Bug 13245023. If your pstack at the moment shows the same call stack, your process is waiting for up to mnt_timeout seconds to open the file on the NFS filesystem. But the bug causes it to loop until counter overflow. mnt_timeout is specified in $ORACLE_HOME/dbs/oranfstab. But I doubt playing with that number helps due to the bug. While waiting for the bug fix, maybe you can have a frequent cron job that opens and closes each file on the NFS just to make sure their inode info is hot in cache?
Yong Huang
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Jan 20 2012 - 10:34:43 CST