On Tue, 07 Feb 2006 10:16:20 -0800 Mike Hardy <mhardy@xxxxxxx> wrote: > > > Chris Osicki wrote: > > > > > To rephrase my question, is there any way to make it visible to the > > other host that the array is up an running on the this host? > > > > Any comments, ideas? > > Would that not imply an "unlock" command before you could run the array > on the other host? Yes, it would. I was thinking about an "advisory" lock, and a well known -f option for those who know what they are doing ;-) > > Would that not then break the automatic fail-over you want, as no > machine that died or hung would issue the unlock command, meaning that > the fail-over node could not then use the disks If I trust my cluster software it's not a problem, I use the -f. My concern is as I said accidentally array activation on the other node. > > It's an interesting idea, I just can't think of a way to make it work > unattended > > It might be possible wrap the 'mdadm' binary with a script that "checks" > (maybe via some deep check using ssh to execute remote commands, or just > a ping) the hosts status and just prints a little table of host status > that can only be avoided by passing a special --yes-i-know flag to the > wrapper It has been done, more or less what you are thinking about. The cluster I'm currently working on is Service Guard on Linux. The original platform is HP-UX. They use LVM for mirroring and device locking is on LVM level. The active cluster node activates a volume group in exclusive mode. This writes a kind of flag onto the disk. Should the node die without a chance to clear the flag, the node taking over the service knows what happened and forces the take-over of the volume group. This feature is missing on Linux. I already have a Linux cluster which has been running for over one year w/o problems. I've just setup three more and to sleep better I'm looking for a way to diminish chances of a disaster due to a operation fault. Regards, Chris > > > -Mike > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
