Re: PHP web clusters and session information

> Date: Thu, 15 May 2008 19:52:20 -0500
> From: <cmarko@...>
> Subject: Re: PHP web clusters and session information
> To: ref <tbs@...>
> Cc: L-blu <discuss@...>
> Message-ID: <ff7a2c351635d134a265c7840e586bbd@localhost>
> Content-Type: text/plain; charset="UTF-8"
>
> I concur with Richard that the simplest method I have found is to simply
> change session.save_path in your php.ini file to an NFS mount.  In my own
> benchmarks, under a moderate simulated web load with hosts mounted against
> the NFS share this performed much better than when trying to use a rather
> simple method of storing it in a MySQL back-end (there is of course a lot
> of room for optimization on the later which I did not consider at the time
> as was looking for simplicity).  This seemed to peak at around 6
> concurrent
> web hosts against the NFS mount point, though I only had 7 physical hosts
> to play with and so don't have insight into the drop-off beyond 7.  I can
> probably dig out my project paper detailing the specs under this testing
> if
> you think it might be of benefit to you.
>
> In theory if you used iSCSI on the back-end for the shared storage with a
> clustered file system (I am thinking GFS, as I don't believe OCFS is
> designed to perform well with the way PHP stores the session files) you
> could scale this well beyond 6 hosts without suffering any performance
> degradation.
>
> If you have the luxury of a BigIP, then you can start to do clever things
> such as using embedded cookies to leverage sticky sessions in pinning
> someone to a specific host in the cluster, etc.  Of course the expense of
> such puts out of reach of most open source projects and hobbyists.