Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 12 Oct 1998 15:17:14 +0200 (CEST) | From | Rik van Riel <> | Subject | Re: ext2fs and shared RAID subsystems |
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On Sun, 11 Oct 1998, Robert Gash wrote:
> Hey, I know this might be a little off-topic, but I need to know if > the ext2fs will work with shared disk subsystems. I need a fully > redundant system for the eMail servers at work, and the only way I > can see having full redundancy (no one point of failure, N+1) is > running 2 mail servers with a shared RAID5 disk subsystem.
Well, shared ext2fs won't work, but I can see another hack that could work...
1. The two servers have something of a token on who keeps track of the filesystem, the other server mounts the FS from the other via NFS (over a local 100Mbit line). 2. The server which does _not_ handle the disk will be named primary server, making the one with the disks less likely to fall over. 3. If the server-with-the-disk falls over, the other one will have to check the filesystems, grab the token and mount the filesystem locally. The fsck will be the (prohibitive?) bottleneck. 4. In the meantime, the other server checks it's own FSes, boots up, cannot grab the token and NFS-mount the disk. When it's up and running, it will become the primary server taking most of the load upon itself, relieving the disk server.
The problem of having to do a filesystem check on switch can not be alliated yet, at least not before Stephen Tweedie and co have finished the yournalling code.
Rik. +-------------------------------------------------------------------+ | Linux memory management tour guide. H.H.vanRiel@phys.uu.nl | | Scouting Vries cubscout leader. http://www.phys.uu.nl/~riel/ | +-------------------------------------------------------------------+
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