> From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss- > boun...@opensolaris.org] On Behalf Of Enda o'Connor - Oracle Ireland - > > Say I have an ldoms guest that is using zfs root pool that is mirrored, > and the two sides of the mirror are coming from two separate vds > servers, that is > mirror-0 > c3d0s0 > c4d0s0 > > where c3d0s0 is served by one vds server, and c4d0s0 is served by > another vds server. > > Now if for some reason, this physical rig loses power, then how do I > know which side of the mirror to boot off, ie which side is most recent.
If one storage host goes down, it should be no big deal, one side of the mirror becomes degraded, and later when it comes up again, it resilvers. If one storage host goes down, and the OS continues running for a while and then *everything* goes down, later you bring up both sides of the storage, and bring up the OS, and the OS will know which side is more current because of the higher TXG. So the OS will resilver the old side. If one storage host goes down, and the OS continues running for a while and then *everything* goes down... Later you bring up only one half of the storage, and bring up the OS. Then the pool will refuse to mount, because with missing devices, it doesn't know if maybe the other side is more current. As long as one side of the mirror disappears and reappears while the OS is still running, no problem. As long as all the devices are present during boot, no problem. Only problem is when you try to boot from one side of a broken mirror. If you need to do this, you should mark the broken mirror as broken before shutting down - Certainly detach would do the trick. Perhaps "offline" might also do the trick. Does that answer it? _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
