[p4] NFS mounted depot

[Nick Dor]

One key point regarding NVIDIA's NetApp implementation is that their
metadata files (db.*) are stored on SAN, thus they are not using NFS for
the journal and db files and still within Perforce support's recommended
best practices.

- Nick

-----Original Message-----
From: perforce-user-bounces at perforce.com
[mailto:perforce-user-bounces at perforce.com] On Behalf Of Weintraub,
David
Sent: Friday, February 17, 2006 11:13 AM
To: Smith, Jeff; perforce-user at perforce.com
Subject: Re: [p4] NFS mounted depot

I had a long talk about this issue with the Perforce support. Most
corporate Unix environments don't backup local drives and normally don't
even give you access to the local disks. Everything is NFS mounted
except for the OS, so if what Perforce states is true, you couldn't use
Perforce in many corporate environments.

I had read the documentation and knew about the locking issue which
would affect the database, but couldn't understand how it would affect
the RCS files. Especially considering that all writes to these files
come from the same server.

I specicially asked you placed the *.db files on a local drive, could
everything else live on NFS. The Perforce support person told me that
the journal and the license file must be local, but that the checkpoint
file and the RCS files could in fact be NFS mounted.

We also discussed backup strategy since I *might* be able to convince my
sysAdmin department to give me local storage for the *.db and journal
files, but I know they won't do local backups at all. Perforce explained
to me that the database files and journal don't have to be backed up
since that's what the checkpoint really does, and the checkpoint file
could be stored on NFS.

Their only recommendation was to store the journal and *.db files on
separate drives controlled by separate controllers. That way, if one
controller fails and completely damages all of the disks attached to it,
you could rebuild the needed information from the other disk drive.

Perforce has a conference paper on their system by NetApps talking about
their experience using Perforce with NetApps.

<http://www.netapp.com/library/tr/3372.pdf>
<http://www.perforce.com/perforce/conf2001/geiger/wprmg.html>


-----Original Message-----
From: Smith, Jeff [mailto:jsmith at medplus.com] 
Sent: Friday, February 17, 2006 1:18 PM
To: Weintraub, David; perforce-user at perforce.com
Subject: RE: [p4] NFS mounted depot

Did they explain the discrepancy between that position and the
documentation?  I just got back a reply from Perforce support that we
should avoid NFS at all costs.

Jeff

-----Original Message-----
From: Weintraub, David [mailto:david.weintraub at bofasecurities.com]
Sent: Friday, February 17, 2006 1:01 PM
To: Smith, Jeff; perforce-user at perforce.com
Subject: RE: [p4] NFS mounted depot


> Should we be wary of moving our depot files, served by a Linux p4d, to
an NFS mount?

I was the one who asked about this very issue and got official word from
on high that the RCS files and the checkpoint files can be stored on NFS
mounted drives. However, the journal and database file need to be stored
on local drives on non-Solaris systems due to this locking issue.
Perforce also recommend storing your journal and db.* files on two
separate drives that use separate disk controllers.

The reason for putting the database and journal on two separate disk
controllers is fairly straight forward: If the database files get
corrupted, they can be rebuilt using the journal. If the journal file
gets hosed, it will automatically be rebuilt when Perforce is restarted.
Your only real issue is if your Perforce server itself gets destroyed
and both the Journal and the database files become damaged. Then, you
have to restore using your checkpoint files, and that means losing all
of your transactions since the last checkpoint operation.

By the way, Perforce recommends never using NFS mounted drives for the
db.* and journal files. For performance reasons, these should always be
on local disks whenever possible.

-----Original Message-----
From: perforce-user-bounces at perforce.com
[mailto:perforce-user-bounces at perforce.com] On Behalf Of Smith, Jeff
Sent: Friday, February 17, 2006 12:29 PM
To: perforce-user at perforce.com
Subject: [p4] NFS mounted depot

There was a thread earlier in which someone indicated that the db.*
files should not be mounted on NFS except using Solaris 2.6 but that the
depot should be no problem.  The Admin guide actually says

"Some issues still remain regarding file locking on non-commercial
implementations of NFS (for instance, Linux and FreeBSD). On these
platforms, store your journal, log, depot, and db.* files on a drive
local to the server machine, not on an NFS-mounted volume."

Should we be wary of moving our depot files, served by a Linux p4d, to
an NFS mount?

Jeff

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