Re: NFS filesystems ok for Oracle tablespace?

Well I think I've successfully hashed this issue out over the last 3 or 4 months. Let me give you my opinion.

Oracle over NFS is fine assuming the following requirements are met: 1) NFS server is available over a low-latency network (i.e. dedicated back-end server with low traffic)

2) NFS protocol is NOT running in a dirty-write mode. That is, it is not telling the client it has successfully written to disk unless it really has done so.. Now w/ a NetApp it writes to its Cache, but according to Netapp the Cache is just as safe as writing to Disk, as it is redundant and go through an Oracle-like two-phase commit. By default NFS V2 and V3 do not do dirty-writes.

3) Keep all database files (control, redo, tablespaces) on the NFS server, that way if the server goes down inconsistencies will not exist between the remote and local filesystems.

Also, don't believe that Oracle will not support an NFS mounted database. This is not true. Their documentation does not specify what sort of filesystems they will and will not support, therefore they are legally bound to support you. I have heard that AOL has already hashed this out with Oracle as they are using NFS (I believe NetApps) and has gotten Oracle to agree to support their configuration.

I have also heard that Oracle and Network Appliance are in the process of coming up with some sort of agreement, hopefully to be made public this Summer.

-Michael
Martin Smith wrote:
>
> I asked about this a few weeks back--we are considering a Network
> Appliance or Falcon NFS server, for cost, flexibility and long-term
> architecture reasons.
>
> What I learned was that Orackle officially does NOT "support" NFS.
> Meaning I guess that they won't entertain a TAR on it.
>
> However, we've tested it and it seems to work, even on a much slower NFS
> device (CD farm on another box.)
>
> I assume that files unavailable will crash Oracle. But we're in a
> waregouse (not transaction) environment and I don't really expect a big
> problem.
>
> I'll report back once the NFS boxes are installed . . .
>
> David Spencer wrote:
> >
> > Does anyone have any comments on the suitability of networked storage
> > hubs for Oracle tablespaces. The beast we have in mind is a vast
> > standalone hub, connected via FDDI, and using NFS (over either TCP or
> > UDP) to make its filestore available to the host. The advantage is
> > said to be that if the host dies then we can mount the filesystem on
> > another host, bring up another Oracle on there, let it recover and get
> > back into service in minutes.
> >
> > Now, I'm worried about the suitability of this for holding Oracle
> > tablespaces. Are you allowed to do that? Does an Oracle server
> > absolutely *need* its disks to be local? What would happen if the
> > storage hub ever said 'stale file handle' to the Oracle server? Or
> > would this never happen in practice, given that we would be unlikely
> > to inconvenience a tablespace data file's inodes in that kind of way?
> > Any comments would be gratefully received.
> >
> > As for performance, well, I shudder to think how much power will be
> > wasted through overheads; but the hub concerned apparently has enough
> > raw power to fritter it away and still give acceptable performance.
> >
> > Yours, worried but not quite knowing why,
> > --
> > Dave Spencer "I lost my bag in Newport Pagnell"
> > Romford, Essex
> > d_at_dsds.demon.co.uk
> > Deltics and Multics and that sort of stuff at http://www.dsds.demon.co.uk/
 

-- 
____________________________________________________________________
Michael Karafotis                               On-Site: BBNPlanet
mkarafot_at_bbnplanet.com                          (617) 873-1907