alf_data moving to network drive

[wiffle]

Is it possible to set the alf_data directory to reside on a machine within the network, using a mapped network drive?

So have the main Alfresco Install on : C\alfresco

Then the alf_data file store on: x:\alf_data

The reason for this is that we have a server that we can run alfresco but another file server that has full mirroring and backup.

If this is possible are there likely to be performance issue when using CIFS or the Webapp?

Any thanks would be greatly appreciated as otherwise we are going to have to op for the expensive option of adding mirroring and backup to the alfresco server as well.

[pmonks]

This is possible provided that the protocol you use to mount the remote drive supports file locking (something that Alfresco tests at startup - you'll get an error message if it doesn't).  I believe most modern remote filesystem protocols (including the native Windows CIFS server, NFS, GFS etc.) support locking, so you should be fine if your configuration is relatively standard.  That said I'd definitely want to test this in a non-production environment first, both functionally and for performance.

As for performance, yes it will suffer across the board and not just with CIFS, but the extent to which it will suffer depends on a large number of factors (network bandwidth and latency between the Alfresco server and the file server, network utilisation, Alfresco and file server utilisations, etc. etc.).  With a few exceptions, Alfresco tends to be I/O bound (both the database and the filesystem that alf_data resides on) and remote file I/O is rarely anywhere near as fast as local I/O (with the possible exception of a SAN technology).

That said if all you want to do is mirror the alf_data directory to another machine for backup purposes you might consider using a replicated content store instead, since this can have most of the performance benefits of a local content store, while still mirroring the content off to a remote content store as well.  See http://wiki.alfresco.com/wiki/Cluster_Configuration_V1.4_to_V2.1.2 for details (even though you're probably not configuring a cluster, the configuration for a replicated content store is the same as for a cluster).

Another thing I would consider is keeping the Lucene indexes local, but configure the backup-lucene-index directory to be on the remote machine.  This will keep Lucene performance high, while still allowing you to backup the Lucene indexes simply by backing up the remote machine's filesystem.

Cheers,
Peter