[gpfsug-discuss] GPFS and both Samba and NFS
jonathan at buzzard.me.uk
Tue Dec 17 21:21:51 GMT 2013
On 17/12/13 03:49, Adam Wead wrote:
> Hi all,
> I've been following this discussion because I use GPFS with both NFS and
> Samba. Although, now I'm a bit concerned because it sounds like this
> may not be an appropriate thing to do. It seems like the issue is the
> clustered implementations of Samba and NFS, yes? Or is this for any
The issue is that running a GPFS cluster with Samba/NFS etc. on top is
not in the same league as installing Linux on a single server with some
storage attached and configuring Samba/NFS.
The system is much more complex and there are nasty ways in which your
data can get corrupted. To proceed for example without a functional
clone test system would be fool hardy in the extreme.
For example in my last job I had a functional clone of the live GPFS
systems. By functional clone that means real hardware, with similar FC
cards, attached to the same type of storage (in this case LSI/Netapp
Engenio based) with NSD's of the same type though fewer running the same
OS image, same multipathing drivers, same GPFS version, same Samba/CTDB
In addition I then had a standalone Samba server, same OS, same storage,
etc. all the same except no GPFS and no CTDB. It was identical apart
from the vfs_gpfs module. One of the reasons I choose to compile my own
vfs_gpfs and insert it into pucka RHEL is that I wanted to be able to
test issues against a known target that I could get support on.
Then for good measure a test real Windows server, because there is
nothing like being able to rule out problems as being down to the client
not working properly with SMB.
Finally virtual machines for building my vfs_gpfs modules. If you think
I am being over the top, with my test platform let me assure you that
*ALL* of it was absolutely essential for the diagnosis of problems with
the system and the generation of fixes at one time or another.
The thing is if you don't get this without being told then running a
GPFS/Samba/CTDB service is really not for you.
Also you need to understand what I call "GPFS and the Dark Arts" aka
"Magic levers for Samba", what they do and why you might want them.
There are probably only a handful of people outside IBM who understand
those, which is why you get warnings from people inside IBM about doing
So by all means do it, but make sure you have the test systems in place
and a through understanding of all the technologies involved as you are
going to have to do support for yourself; you cannot ring IBM or RedHat
and say my GPFS/Samba/CTDB storage cluster is not working as you are
well of the beaten path. Sure you can get support from IBM for GPFS
issues provided it is entirely GPFS related, but saving from Office 2010
on a shared drive with rich permissions is giving wacked out file
ownership and permission issues is going to be down to you to fix.
Jonathan A. Buzzard Email: jonathan (at) buzzard.me.uk
Fife, United Kingdom.
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