[8993] in linux-scsi channel archive
Re: multi-initiator?
daemon@ATHENA.MIT.EDU (Erling Nygaard)
Thu Jun 15 10:50:32 2000
Date: Thu, 15 Jun 2000 09:45:49 -0500 (CDT)
From: Erling Nygaard <nyga0031@tc.umn.edu>
Reply-To: Erling Nygaard <nygaard@borg.umn.edu>
To: linux-scsi@vger.rutgers.edu
In-Reply-To: <20000615151531.Y1889@garloff.tue.nl>
Message-Id: <Pine.SOL.4.20.0006150942570.499-100000@garnet.tc.umn.edu>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Thu, 15 Jun 2000, Kurt Garloff wrote:
> On Wed, Jun 14, 2000 at 08:49:22PM -0500, Ralston, Steve wrote:
> > There's been some recent discussion and questions 'round here
> > about multi-initiator setups on linux. From what I can determine,
> > the linux scsi mid-layer doesn't do any sort of RESERVE / RELEASE
> > stuff. (RESERVE_10, RELEASE_10 weren't even defined in
> > <scsi/scsi.h> until very recently).
>
> No. And it would be cleared by the exception handling as sooner or later you
> would get a SCSI reset because of the reservation conflicts ...
>
> > So with two or three linux systems attached to the same fibre channel
> > (loop in this case:-), I can mount the same target (ext2 f.s.) from
> > any+all the systems and (blindly+) merrily work away...
> > while eventual multiple writes clobber the file system, right?
>
> A single write can be enough, as all the other hosts now see an
> insconsistent filesystem, containing old data from the buffer/page cache and
> new one read from the disk.
>
> > Or is this handled via some other mechanism?
> > + Driver(s) responsible for handling any+all multi-initiator issues.
> > + LVM, clustering, or somesuch?
>
> No.
> Of course, you can design software to handle this ...
>
There is of cource the Global File System (GFS) which will allow you to
have all the hosts share the file system... (Both read & write)
http://www.globalfilesystem.org
Erling
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