samba - Feb 2008 - Performance issues after samba update (utime?)

Hi all,

We're experiencing performance issues after migrating from 3.0.8 to 3.0.28.
Write performance has degraded about 30%, regardless of the size of file
being copied. (tests described below are a single 150Mb file copy from an XP
explorer)

The setup is somewhat peculiar as the server is mounting NFS shares (v3) and
exporting these.
smb.conf hasn't changed, save for the addition of "msdfs root =
no"

Comparing smbd truss output between these version shows a likely culprit :
3.0.28 is doing lots of utime() calls, and these take a long time on an NFS
share.

Someone seems to have encountered this issue before :
http://readlist.com/lists/lists.samba.org/samba/3/16790.html

But I see no followups to this.
Any way to fall back to the old behavior, with less utime calls ?
Failing that I'd be happy to get any recommandations you guys might have in
order to mitigate the issue (or tell me that this is a red herring and I
should look elsewhere :-) )

A few details on the environment : solaris 10, nfs v3 with mount options set
to hard,tcp,rsize=4096,wsize=4096

Cheers

-- 
Alex

On Tue, Feb 26, 2008 at 11:57 PM, Alex Still <alex.ranskis@gmail.com>
wrote:
> Hi all,
>
> We're experiencing performance issues after migrating from 3.0.8 to
3.0.28
> .
> Write performance has degraded about 30%, regardless of the size of file
> being copied. (tests described below are a single 150Mb file copy from an
XP
> explorer)

[..]

I think I found it.
Samba-3.0.28 calls set_filetime() from real_write_file(), which 3.0.8 isn't
doing.
set_filetime -> utimes -> nfs SETATTR (in my case)
After removing that bit from real_write_file, I get exactly the same
performance I had before. Now, I realise this has probably been put there
for a reason...

Stuck now, any advice on the matter appreciated

Cheers,

-- 
Alex