[Linux-cluster] GFS performance issue on CentOS 5.5

[Gordan Bobic]

Fred Wittekind wrote:
>  I do have noatime, need to add nodiratime.

noatime is a superset of nodiratime.

> There are PHP session files
> on the gfs2 volume.  There used to be Zend Cache file on it, but I moved
> those to tmpfs.  There is one other set of cache files that where put in
> a bad directory, so they are hard to move to tmpfs without changing the
> client's website code (although I may do this anyways).

Indeed you may, that sounds like a good place to start looking for your 
performance problems.

> I had considered moving the PHP session files to a memcache server, but
> then I observed very long load times on static website content
> (images).  Since images don't involve the session files, I had decided
> that it looked like there was more of a problem than the session files. 
> Although, could lock issues with the session files effect load times of
> files in a completely different area of the directory tree?

Session files will be accessed for ever page hit, will they not?

Gordan