samba-vms Digest, Vol 8, Issue 15

[Stephen Eickhoff]

On Wed, 27 Aug 2003 12:06:38 +0000 (GMT), samba-vms-request at lists.samba.org
wrote:

>Message: 3
>Date: Wed, 27 Aug 2003 13:25:13 +0200
>From: COLLOT Jean-Yves <jean-yves.collot at cofiroute.fr>
>Subject: RE : New samba not starting
>To: "'Brian Tillman'" <Brian.Tillman at Smiths-Aerospace.com>,
>	samba-vms at lists.samba.org
>Message-ID:
>	<CF0913E9C3D53D4E94DE47FDE25C633D0234CA75 at hermes.cofiroute.com>
>Content-Type: text/plain
>
>Hi.
>
>That's my fault. For performance reasons, I changed the default Samba/VMS
>option for "oplocks" to "No".
>
>I must admit I don't clearly understand what those oplocks are and what they
>are supposed to do. I just saw that when enabled, they add activity of IP
>messages between the smbd processes on the VMS server, and the overall
>performance is worst. I know that the Samba documentation claims that "The
>oplock code can dramatically (approx. 30% or more) improve the speed of
>access to files on Samba servers". In my experience, it may be true on Unix,
>but it's not true on VMS. 
>
>If I'd known better, I would have changed the "level2 oplocks" default to
>"No" too, in order to avoid the warnings in TESTPARM. I'll do it for the
>next release.

Opportunistic locking is used to improve client performance by caching network
data locally. Its primary use is for database access, so that individual
records can be cached without locking the entire file (definitely
unacceptable). This works because the server grants the lock only when it is
convenient, and notifies the client when it must be broken.
----------------------------------
        Stephen Eickhoff
      operagost at email.com
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