----- Forwarded message from Andrew Tridgell <[EMAIL PROTECTED]> ----- From: Andrew Tridgell <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED], [EMAIL PROTECTED] Subject: Re: Fwd: Re: Fwd: Re: Samba and "opportunistic file locking"? Date: Fri, 21 Sep 2001 15:15:33 -0700 (PDT) Reply-To: [EMAIL PROTECTED] Gordon, It's a bit hard to follow all the quoting in this email, so maybe I should just restate a few facts. 1) turning oplocks off in Samba will NOT cause file corruption. With oplocks off the clients will use synchronous IO operations. 2) oplocks have nothing to do with share modes (aka deny modes) or byte range locking. The primary mechanism in Windows for preventing corruption on simulantaneous usage is share modes. The secondary mechanism is byte range locks. 3) enabling oplocks does not play a role in preventing corruption, but if you enable them and you have simultaneous access to files by oplock aware apps and non-oplock aware apps then you can get corruption because the non-oplock aware apps won't see the cached data. That is why I recommended disabling oplocks in your config - I believe you were experiencing file corruption on a 2.2 kernel with Samba when files were being shared between windows clients and non-windows apps. 4) With the 2.4 kernel Samba is told by the kernel when a non-oplock aware app tries to access the file. The access is blocked until Samba is able to dispense with the oplock. In summary it is always safe to disable oplocks, but there is a performance hit that is sometimes quite large. With the 2.4 kernel you can safely enable oplocks which gains you performance without any risk. Cheers, Tridge ----- End forwarded message ----- Gordon Rowell [EMAIL PROTECTED] VP Engineering Network Server Solutions Group http://www.e-smith.com Mitel Networks Corporation http://www.mitel.com -- Please report bugs to [EMAIL PROTECTED] Please mail [EMAIL PROTECTED] (only) to discuss security issues Support for registered customers and partners to [EMAIL PROTECTED] To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Archives by mail and http://www.mail-archive.com/devinfo%40lists.e-smith.org
