>> And backups are sucky unless you do NDMP directly to tape. But then >> restores suck suck suck because NDMP is just an encapsulation of the >> native dump/restore tools, which means scanning the tapes bit by bit >> to find and restore the file(s) you want to restore. So in that case, >> snapshots make a huge difference. Except when they expire and the >> user comes the next day with a restore request.
Edward> This was a huge win for us, in favor of ZFS. No major arguements. Edward> Previously we had the NetApp with scsi attached tape library, Edward> controlled via NDMP. A total approx 1Tb storage used. The Edward> backup window was approx 10 hrs per night, and 30 hours for Edward> full backup on the weekend. The scsi bus would sometimes mess Edward> up and cause the system to crash or reboot, approx 2-3 times a Edward> year, which should of course be zero. Very annoying. Sounds like you had both crappy tape drives, and just poor performance over the SCSI bus. From another email, I see you had a StoreVault thingy, which is NOT enterprise class Netapp hardware. Edward> When we got the sun fileserver, we also bought some cheap Dell Edward> and installed solaris on it too. Hook up the tape autoloader Edward> to the Dell. ZFS send to the Dell, and from there backup to Edward> tape. Now our backup window (zfs send) is about 7 minutes per Edward> night, and about 10 hrs to do the full. After that, I don't Edward> know and don't care how long it takes to write the tapes, Edward> because whatever the load is and however long it lasts, it's Edward> not happening on my production system. Even if the scsi bus Edward> crashes, no big deal because it's just the secondary backup Edward> server, not the production server. Nice setup. How many snapshots can you store on the Dell or the Sun and how often have you had to restore from Tape? Edward> I can't emphasize this enough, it was a huge win to send snaps Edward> server-to-server-to-tape. Sure, but you now need to have double (if not more!) storage, and twice as many systems to manage. So you went from a single Netapp box, to a pair of boxes running Solaris with ZFS. Of course you got better performance! Edward> Yes you could do the same thing with NetApp, but you would Edward> have to buy two units, plus the SnapMirror licensing. We are Edward> talking *way* more expensive to do the same thing with the Edward> NetApp. Sure, you'd need to buy two sets of hardware for the same type. No arguement. But I'll also argue that a FAS3140 will have the horsepower to push your SCSI tape drives all day and night and you'd never notice it. But restores from Tape are going to suck if you only need/want a single file or a couple of files. And you haven't addressed that usage scenario at all. Sure, restores from snapshots are trivial. Never argued they weren't. And I personally *like* snapshot restores. But when an engineer creates a 500+gb file during a simulation run, it will simply *kill* your snapshot reserve, and reduce the usefulness of snapshots remarkably. This is the hidden killer issue of snapshots, single large chunks of temporary data which get put into snapshots by accident are painful. Suddenly you need to clean out snapshots more quickly than you planned, and then you're back to tape. Remember, users do NOT care about backups. Ever. They only care about restores. John _______________________________________________ bblisa mailing list [email protected] http://www.bblisa.org/mailman/listinfo/bblisa
