Hmm... thinking about this more (and bear in mind I'm having to guess about internal workings here as I'm very new to ZFS, SAN's, clustering and iSCSI), if you use iSCSI for the clustering, you've got the problem of what's actually being saved to each system, and how do you track it.
You'd need to be implementing a file system for this to work wouldn't you? So in essence, you'd be repeating effort for a lot of the stuff in ZFS. So then I thought about shoehorning iSCSI support inside of ZFS, but I think I've read that's already possible - you can use an iSCSI target as a raw disk for ZFS? If that's the case, you can actually distribute ZFS already across multiple systems, using striping, mirroring, even raid-z2. The only problem is you have a single point of failure in the ZFS host. Which then makes sense of the current plans to implement clustering support for ZFS. If you can cluster that, and you can cluster iSCSI targets, you then have a highly available ZFS service where the data can also be stored on a distributed network of servers. Going a stage further, if you consider the individual servers providing the iSCSI targets for this. They can also be running ZFS internally. So you're using two layers of ZFS - one guarding against disk failure, and another guarding against host / controller / network failure. And because it's ZFS, you're also doing checksummed data integrity checking on all your network traffic. SWEET! I think this also means you could hot swop or retire servers really easily. Just use zpool replace on the network ZFS and all of a sudden retiring an old server and bringing in a new one is a piece of cake. At the most basic level I wonder if you'll be able to implement this with just two servers (would handy as we're probably buying two thumpers shortly). Run ZFS on each sharing it out over an iSCSI target. Then also run HA-ZFS on each box (can I do that at the same time?), and have that create a mirrored set of the two iSCSI targets. Then use HA-iSCSI and (fingers crossed) HA-CIFS to make that available on your network (in our case to windows servers and clients). If that works, voila! Instant, cheap, easy to manage, and superbly realiable storage for any network you care to imagine. And it's scalable and expandable too. Either by upgrading the individual drives, by replacing the thumpers with bigger ones (lol, let me dream) and using zpool replace, or by adding extra servers with zpool add. Now *that's* what I call an enterprise file system (and affordable for small companies too!) This message posted from opensolaris.org _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
