[Linux-cluster] [Fwd: Re: [Iscsitarget-devel] iSCSI on Fedora Core 5 or custom]

[Erling Nygaard]

Brenton

GFS does not depend on any of the SCSI Release, Reserve or persistent
reserve commands.
GFS does not really depend on SCSI at all, just so happens that most
shared storage devices are SCSI based :-)


Once upon a time, in a galaxy far, far away GFS did attempt to use
special SCSI commands for locking. The attempt was discontinued....

Erling

On 4/18/06, Brenton Rothchild <brentonr at dorm.org> wrote:
> Hello!
>
> There has been some minor discussion on the iscsitarget-devel list
> regarding the fact that the current iscsitarget code doesn't fully
> implement the SCSI commands Release and Reserve, nor does it implement
> persistent reserve in/out.
>
> It was also mentioned that some cluster software, such as
> MSCS (Microsoft Cluster), will possibly corrupt data.
>
> It was then asked if GFS would depend on these unimplemented
> SCSI commands, and the response from Ming Zhang (below) wasn't 100%
> sure.
>
> So, would an iSCSI target lacking Release, Reserve, and persistent
> reserve in/out cause problems with GFS?
>
> Thanks!
> -Brenton
>
> -------- Original Message --------
> Subject: Re: [Iscsitarget-devel] iSCSI on Fedora Core 5 or custom
> Date: Tue, 18 Apr 2006 17:16:39 -0400
> From: Ming Zhang <mingz at ele.uri.edu>
> Reply-To: mingz at ele.uri.edu
> To: Jos Vos <jos at xos.nl>
> CC: iscsitarget-devel at lists.sourceforge.net
>
> On Tue, 2006-04-18 at 22:50 +0200, Jos Vos wrote:
> > On Tue, Apr 18, 2006 at 04:21:29PM -0400, Ming Zhang wrote:
> >
> > > cluster like MSCS, cluster file system mostly depends on scsi command
> > > like reserve/release, persistent reserve in/out. But IET does not really
> > > implement them. So there will be chance that you fail the cluster and
> > > corrupt u data.
> >
> > Does this also apply to the GFS and OCFS2 filesystems?
>
> i am not 100% sure, but i remember that once a GFS guy told me that GFS
> will run ok even with persistent reserve in/out support. not sure about
> OCFS2.
>
> Ming
>
>
>
>
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