Date: Mon, 24 Apr 2000 10:20:05 -0600 From: "Kenneth D. Merry" <ken@kdm.org> To: sthaug@nethelp.no Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: Safe mounting of one file system on multiple hosts? Message-ID: <20000424102005.A10563@panzer.kdm.org> In-Reply-To: <70070.956589300@verdi.nethelp.no>; from sthaug@nethelp.no on Mon, Apr 24, 2000 at 05:15:00PM %2B0200 References: <70070.956589300@verdi.nethelp.no>
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On Mon, Apr 24, 2000 at 17:15:00 +0200, sthaug@nethelp.no wrote: > I have a RAID system from Nexsan (www.nexsan.com), which is basically > two CMD CDR-5644 controllers in a hot-standby configuration. The system > has two host channels, and two disk channels. I have two different hosts > connected to the two hosts channels. > > Normally, I would configure two (or more) RAID sets, and have each RAID > set dedicated to one host (visible on only one of the host channels). > Each RAID set appears to the host as one disk - and can be partitioned, > newfs'ed etc. with normal FreeBSD tools. This works fine. > > However, I also have the *option* of making all RAID sets visible on > *both* host channels. I don't want to try read/write mounting one RAID > set on two hosts - but can I safely read/write mount the RAID set (its > corresponding file system(s)) on one host, and mount it readonly on the > other host? I guess the basic question is: Will a readonly mount of a > file system lead to *zero* writes to this file system? I would recommend that you test out the controller carefully under high load conditions if you have more than one array configured on it. There have been a number of reports (see the list archives) about problems with CMD RAID arrays with more than one LUN (i.e. more than one array) configured. As for the mount question, it should work, but I haven't actually done it, so I can't say for sure. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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