[CentOS] htdocs on NFS share / any pitfalls?

Wed Oct 23 15:18:30 UTC 2013
Les Mikesell <lesmikesell at gmail.com>

On Wed, Oct 23, 2013 at 4:01 AM, Leon Fauster
<leonfauster at googlemail.com> wrote:
> Am 23.10.2013 um 07:52 schrieb James A. Peltier <jpeltier at sfu.ca>:
>> | i have a new setup where the htdocs directory for the webserver
>> | is located on a nfs share. Client has cachefilesd configured.
>> | Compared to the old setup (htdocs directory is on the local disk)
>> | the performance is not so gratifying. The disk is "faster" compared
>> | to the ethernet link but the cache should at least compensate this
>> | a bit. Do they exist more pitfalls for such configurations?
>> |
>> The best thing to do with respect to NFS shares is to make extensive use of caching
>> in front of the web servers.  This will hide the latencies that the NFS protocol will
>> bring.  You can try to scale NFS through use of channel bonding or pNFS/Gluster but
>> setting up a reverse proxy or memcached instance is going to be your best bet to making
>> the system perform well.
> All web-frontends (multiple) have the filesystem caching already in
> place (bottom layer). The application uses a key-value-store in memory (top layer) to
> accelerate the webapp (php). Nevertheless the performance is not satisfying. I was looking
> at some caching by the httpd daemon (middle layer). Any experiences with such apache
> cache out there?

What kind of throughput and latency are you talking about here?   NFS
shouldn't add that much overhead to reads compared to disk head
latency and if you enable client caching  might be considerably
faster.   If you are writing over NFS you don't get the same options,
though and sync mounts are going to be slow.

   Les Mikesell
      lesmikesell at gmail.com