Theodore Tso wrote: > On Thu, Aug 28, 2008 at 09:58:10AM -0500, Eric Sandeen wrote: >> I was talking to Ric about dump benchmarks, and he was of the impression >> that dump may not be used that often anymore, at least in the >> enterprise. > > Many people don't use the dump/restore any more program any more, > that's definitely true. Whether people use backups (as opposed to > large amounts of RAID) in the enterprise is a different question. I'm > not so sure about the second question. > > So a couple of comments. First, it's probably not fair to use > different backup programs for the different filesystems. Well, if a filesystem has a dedicated, presumably optimized backup utility, why would you not benchmark that as part of the mix? :) > We probably > want to do one set of comparisons where we use tar for all three. Yep, I'm doing that now ... also realized I tested on an inappropriate elevator (cfq) for a fancy-raid. I'll resend in a bit. > (Note: not all backup/dump programs are doing the right things with > xattr's, so we're not necessarily comparing programs with completely > identical functionality.) well, tar supposedly is with the options I gave it, xfsdump certainly does, and dump, I dunno offhand. > Secondly, it really wouldn't be hard to update dump/restore for ext4. > It uses libext2fs, so the real problem is that it is explicitly > checking the feature flags. Removing those checks may be all that is > necessary, given that ext2_block_iterate() still works for > extent-based files. Eh, I'll test that then. > I just noted BTW that the dump/restore doesn't > seem to be TOTALLY abandoned. It was last updated in 2006, true, but > there is support for backing up and restoring extended attributes and > ACL's. Ah, ok, so they all should be backing up acls/attrs then. > I wonder if they broke format compatibility with BSD 4.4 > format dump/restore backups when they did it --- and if anyone would > still cares. :-) > > Finally, I suspect most of the problem with using tar is the HTREE > dirent sorting problem. If we modify tar to sort the directory > entries before emitting the files, and then use that tar across all > the filesystems, I suspect the results would be much more better for > ext3 and ext4. True enough, just testing what we have now. I can play with acp... -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
