Well, that's a good reason to get rid of those Solaris servers. :-)
Seriously, though, we do _not_ fix server bugs by changing the client.
If we had been doing something that was incorrect, or not recommended
by the NFS spec, then matters would be different...
Trond
On Jun 4, 2009, at 17:30, Brian R Cowan <brcowan@xxxxxxxxxx> wrote:
I'll have to see if/how this impacts the flush behavior. I don't
THINK we
are doing getattrs in the middle of the link, but the trace
information
kind of went astray when the VM's gor reverted to base OS.
Also, your recommended workaround of setting no_wdelay only works if
the
NFS server is Linux, the option isn't available on Solaris or HP-UX.
This
limits it's usefulness in heterogenous environments. Solaris 10
doesn't
support async NFS exports, and we've already discussed how the small-
write
optimization overrides write behavior on async mounts.
=================================================================
Brian Cowan
Advisory Software Engineer
ClearCase Customer Advocacy Group (CAG)
Rational Software
IBM Software Group
81 Hartwell Ave
Lexington, MA
Phone: 1.781.372.3580
Web: http://www.ibm.com/software/rational/support/
Please be sure to update your PMR using ESR at
http://www-306.ibm.com/software/support/probsub.html or cc all
correspondence to sw_support@xxxxxxxxxx to be sure your PMR is
updated in
case I am not available.
From:
Trond Myklebust <trond.myklebust@xxxxxxxxxx>
To:
Brian R Cowan/Cupertino/IBM@IBMUS
Cc:
Carlos Carvalho <carlos@xxxxxxxxxxxxxx>, linux-nfs@xxxxxxxxxxxxxxx,
linux-nfs-owner@xxxxxxxxxxxxxxx
Date:
06/04/2009 04:57 PM
Subject:
Re: Link performance over NFS degraded in RHEL5. -- was : Read/Write
NFS
I/O performance degraded by FLUSH_STABLE page flushing
On Thu, 2009-06-04 at 16:43 -0400, Brian R Cowan wrote:
What I'm trying to understand is why RHEL 4 is not flushing anywhere
near
as often. Either RHEL4 erred on the side of not writing, and RHEL5 is
erring on the opposite side, or RHEL5 is doing unnecessary flushes...
I've
seen that 2.6.29 flushes less than the Red hat 2.6.18-derived
kernels,
but
it still flushes a lot more than RHEL 4 does.
Most of that increase is probably mainly due to the changes to the way
stat() works. More precisely, it would be due to this patch:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git&a=commitdiff&h=70b9ecbdb9c5fdc731f8780bffd45d9519020c4a
which went into Linux 2.6.16 in order to fix a posix compatibility
issue.
Trond
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