Re: Disk file operations I/O

  • From: Yong Huang <yong321@xxxxxxxxx>
  • To: kylelf@xxxxxxxxx
  • Date: Fri, 20 Jan 2012 08:34:43 -0800 (PST)

> 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
--
//www.freelists.org/webpage/oracle-l


Other related posts: