[Gluster-users] NFS file locking with gluster 3.7.3

[Thibault Godouet]

Thanks Anand.  That would be interesting to see indeed.
On 17 Aug 2015 4:55 am, "Anand Subramanian" <ansubram at redhat.com> wrote:

> Hi Thibault,
>
> There are a few tuneables that have helped boost ganesha performance and I
> suspect these tuneables on the OS side apply to improve performance for
> several workloads where ganesha is concerned. (And they don't seem to be
> necessary for gluster-nfs at all).
>
> Adding Manoj here, who may be able to point you to these configurables
> (as he has experimented with the ganesha performance).
>
> Thanks,
> Anand
>
> On 08/13/2015 07:13 PM, Niels de Vos wrote:
>
> On Mon, Aug 10, 2015 at 09:19:25AM +0100, Thibault Godouet wrote:
>
> Thanks Niel for your helpful answer.
>
> Regarding the locking, indeed that solves my issue. Now I'm wondering how
> to monitor this. The best I have so far is get the list of RPC binds and
> the TCP/UDP port in particular, and then run a lsof to find out if it is
> Gluster.  Should work, but a bit indirect. If someone knows a better way
> I'd be interested to know.
>
>
> That is almost how I do it as well. Instead of 'lsof' I use 'netstat' or
> 'ss', depending on the Linux distribution.
>
>
> As for Ganesha, I saw articles explaining that it effectively removes
> layers, hence why I thought NFS v3 via Ganesha would be faster than native
> Gluster NFS.  Given your answer I take it there are other moving parts /
> differences.  Is there a general known guideline on which is best when?
> E.g. does one handle better small files than the other one or something
> like that?
>
>
> I am not aware of any guidelines for this. The difference in performance
> is highly dependent on the workload and use-case. There is little
> difference in the layers between Gluster/NFS and NFS-Ganesha, both are
> userspace nfs-server implementations (neither has context switches for
> the Linux-VFS like fuse mounts have).
>
> If you need the best performance, you should problaby just try both
> configurations, and run your intended workload against the servers.
> Artificial/standard tests most often do not emulate a real workload.
>
> HTH,
> Niels
>
>
>
> On 5 Aug 2015 7:06 pm, "Niels de Vos" <ndevos at redhat.com> <ndevos at redhat.com> wrote:
>
>
> On Wed, Aug 05, 2015 at 04:11:47PM +0100, Thibault Godouet wrote:
>
> Looking around I get the impression that file locking (NLM) may simply
>
> not
>
> be supported in glusterfs's built-in NFS server.
>
>
> This is actually supported. But note that you can not run a userspace
> NLM implementation provided by a NFS-server (Gluster/NFS or NFS-Ganesha)
> on a system that acts as an NFS-client. The Linux kernel NFS-client uses
> the lockd kernel module, and there can be only one NLM implementation be
> registered at rpcbind. Whichever service (nfs-client or nfs-server)
> starts first, will be able to register itself, the 2nd one will (mostly
> silently) fail.
>
>
> I get the impression that Ganesha is aimed at supporting NFS better, and
> presumably supports locking well, so I should give it a try (If I
> understand well the performance is also likely to be higher, which is a
> nice bonus!)
>
>
> NFS-Ganesha offers more features than Gluster/NFS. The performance is
> highly dependent on the workload, Gluster/NFS can be faster for many of
> them.
>
> Cheers,
> Niels
>
>
>
>
> If someone could confirm this that would be useful to make sure I'm going
> in the right direction.
>
> Thanks,
> Thibault.
> On 4 Aug 2015 1:23 pm, "Thibault Godouet" <tibo92 at godouet.net> <tibo92 at godouet.net> wrote:
>
>
> Hi,
>
>
>
> I have a cluster of 2 servers running 3.7.3 with replication, and
>
> standard
>
> NFS (no ganesha).  This in on CentOS 6.
>
> I use CTDB with 2 virtual IPs (one for each server in a normal
> situation) to share the volume over NFS and CIFS (samba).
>
>
>
> fnctl() file locking doesn't seem to work when the volume is mounted
>
> over
>
> NFS.
>
> This is apparent with a 'svn info' (svn 1.8 if it made any difference)
>
> in
>
> a local working copy:
>
>
>
> $ svn info
> svn: E200033: Another process is blocking the working copy database, or
> the underlying filesystem does not support file locking; if the working
> copy is on a network filesystem, make sure file locking has been
>
> enabled on
>
> the file server
> svn: E200033: sqlite[S5]: database is locked, executing statement
>
> 'PRAGMA
>
> synchronous=OFF;PRAGMA recursive_triggers=ON;PRAGMA
>
> foreign_keys=OFF;PRAGMA
>
> locking_mode = NORMAL;'
>
>
>
> a strace shows:
>
>
>
> $ svn info
> svn: E200033: Another process is blocking the working copy database, or
> the underlying filesystem does not support file locking; if the working
> copy is on a network filesystem, make sure file locking has been
>
> enabled on
>
> the file server
> svn: E200033: sqlite[S5]: database is locked, executing statement
>
> 'PRAGMA
>
> synchronous=OFF;PRAGMA recursive_triggers=ON;PRAGMA
>
> foreign_keys=OFF;PRAGMA
>
> locking_mode = NORMAL;'
>
>
>
> Everything seems to work fine on native Gluster (FUSE) mounts: the same
> 'svn info' works nicely.
>
> I can't really use native mounts due to the performance hit (many small
> files) and the fact I would need to install the gluster client
>
> software on
>
> every server.
>
>
>
> Is fnctl() file locking supported in Gluster NFS mounts?  If so, any
>
> idea
>
> why it doesn't work for me?
>
>
>
> Thanks,
>
> Thibault.
>
>
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