On Mon, Mar 1, 2010 at 5:39 PM, Nicholas Leippe <[email protected]> wrote: > On Mon, Mar 1, 2010 at 5:31 PM, Michael Torrie <[email protected]> wrote: >> So I have a number of Xen Dom0 hosts that are all connected to a fibre >> channel fabric. Some of my DomU machines employ software RAID across >> two physical LUNs brought in from the fibre channel arrays. The reason >> I do this is to get a bit more redundancy. Should the power fail on one >> chassis or the cable gets damaged, the VMs can still function. Anyway >> the problem is that when the Dom0 host boots up, it sees all the volumes >> on the fabric (right now some 20 scsi devices in /dev) and then proceeds >> to scan and assemble all the RAIDs it finds. This is exactly what I >> don't want to happen as having the Dom0 assemble the RAID and then >> booting the DomU which will also assemble same RAID will be very bad indeed. >> >> I've heard that you can label the superblocks on the RAID members with >> hostname so they won't auto-assemble except on their proper host. But >> the RAIDs were created by the RHEL installer and I have no idea if they >> were labeled or not. I can't find any information on this other than >> vague references. The man page of mdadm isn't of any help here as well. >> >> Does anyone know more about this or can give me ideas? > > You can pass raid=noautodetect to the kernel to prevent it from > enumerating any md devices. >
The option you're looking for is --homehost= during array creation. It affects the metadata, and depending on the superblock version you chose the UUID. I don't know if you can change it after-the-fact. I do know that only 0.90 superblocks is supported for some operations (booting off of raid1 I believe is one of them), despite the 1.0 version being several years old and improved in a few ways. Go figure. /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
