apache document root on nfs share - Good idea?

adm

Hi,
Not sure if this is the right forum for this but anyhoo...

We are planning to move our servers to a load balanced
solution with 2 application servers, a database server,
and a server for storage.
I plan on mounting a directory from the storage machine as
an nfs share on both the application servers and
using this as the apache document root,
thus , effectively , implementing shared storage.
I also plan on storing php session data in the same fashion
in order to avoid any problems with session stickyness.

I would like to know peoples opinions on using
nfs in this way as a simple shared storage solution
for load balanced websites.
Any advice would be greatly appreciated.
I have googled and cant find any sites advising against doing it.
Thanks

cgarvey

Any sense of throughput, or bandwidth?

If you have a high volume of low-resource requests, then there's potential for NFS to become a bottleneck (especially if you don't have dedicated ethernet between the 2 machines.

I maintain some high-volume sites (high transaction, low resource.. mid-transaction, high-resource). However on the higher-transaction sites, I don't use file-based sessioins (as NFS requests did start queuing up), but a distributed memory cache (memcached being my current choice).

If you have a decent througput site, then you'll need to isolate "internal". SoftLayre.com do this out of the bag, but most other big centres also do this at an additional charge.

I wouldn't advise against it, for a medium traffic site, but it really is down to the traffic/throughput.

adm

Thanks for the reply.
memcached may be the way to go in future.

The machines are on their own vlan with gigabit ethernet.

We see bandwidth of around 2GB per day.