[Samba] Slow Samba writes over NFS
Volker.Lendecke at SerNet.DE
Mon Jul 21 16:47:32 GMT 2008
On Mon, Jul 21, 2008 at 11:14:59AM -0500, ashis.v.purbhoo at exxonmobil.com wrote:
> Thanks for the suggestions, putting Samba directly on the file server would
> be ideal, but due to the environment & the large number of Linux/Unix file
> servers, this is not a likely scenario. Unfortunately, the only current
> option is for us is to use Samba accessing data over NFS. From my
> understanding several factors went into deciding on Samba v2.0.10 and among
> that were NFS data integrity, smbd hanging and & non-use of *tdb's. At
> some point in time we had to go from Samba v2.2 back to Samba v2.0.10 for
> the above reasons.
> Suggestions received to speed NFS writes on Samba v3 vs. Samba v2:
> Set "strict locking = no" (default in Samba v2*). Default in Samba v3
> is "strict locking = yes"
> Set "posix locking = no"
> The utimes(2) calls may have changed for write for correctness...
"strict locking" or even "locking" should not be touched.
"posix locking = no" is advisable for sharing NFS imports.
> With or without the suggested updates above, is Samba susceptible to NFS
> data corruption and smbd hangs? Was the utime code/script update to really
> address NFS write correctness, or other?
The utimes stuff is not an NFS specific thing, the problem
though is that it is orders of magnitude slower over NFS
than on a local file system.
smbd hangs when re-exporting NFS are most likely NFS client
bugs that Samba can not work around. If smbd is stuck in D
state in a file system syscall like pread(2) or unlink(2),
there is NOTHING that Samba can do. This is a kernel issue.
> I need to determine if any/all of these items below have substance/still
> hold true for Samba v3* and specifically for Samba 3.0.27a.
> Does these websites info. still hold true for Samba 3.0.27a?
> Issues around Samba 3.0.5:
Beyond "posix locking = no" please also set "kernel oplocks
= no". Then depending on the quality of your NFS client
implementation you could get to a working server.
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