<br><br><div><span class="gmail_quote">On 3/6/08, <b class="gmail_sendername">Daniel Pittman</b> <<a href="mailto:daniel@rimspace.net">daniel@rimspace.net</a>> wrote:</span><blockquote class="gmail_quote" style="margin-top: 0; margin-right: 0; margin-bottom: 0; margin-left: 0; margin-left: 0.80ex; border-left-color: #cccccc; border-left-width: 1px; border-left-style: solid; padding-left: 1ex">
Michael Hipp <<a href="mailto:Michael@Hipp.com">Michael@Hipp.com</a>> writes:<br><br>> Oliver Brakmann wrote:<br> >> On Wed, 2008-03-05 17:04, David Kempe wrote...<br> ><br> >>> Importantly, you can have data-loss on XFS if you lose power suddenly,<br>
>>> perhaps more so than ext3. When files get corrupted on XFS, I have<br> >>> noticed they go to zero size<br> >><br> >> I believe I read somewhere that that has been fixed some time ago.<br>
><br> > Oliver, could you perchance find a reference for that? Dapper really<br> > isn't that old.<br><br><br>The change was in 2.6.24, so will be in Hardy, but is not present in any<br> file system before that.<br>
<br> There were some data corruption bugs around 2.6.17, none of which were<br> ever in an Ubuntu release that I am aware of, and which have since been<br> fixed; these are unlikely to be what the posters here are describing.[1]<br>
<br><br> > Not disagreeing. I'd *like* to use XFS, I just feel burned by it. An<br> > indicator that this issue has been solidly addressed would be great<br> > news.<br><br><br>It should be more or less as solid as writeback ext3 now, but less safe<br>
than data journaled ext3.<br><br><br> > Some things to read:<br> > <a href="http://www.debian-administration.org/articles/388#comment_40">http://www.debian-administration.org/articles/388#comment_40</a><br> > (read all comments to the end)<br>
<br><br>This comment, and the few subsequent, are a misunderstanding of how<br> things work. The problem illustrated is not that "enterprise<br> applications do their own data recovery."<br><br> The problem is that POSIX file semantics make some things safe and some<br>
things dangerous regarding your files. The applications that see NULL<br> content would probably be corrupt on disk, since they have changed their<br> size and (potentially) appended random data to the end of their content.<br>
<br> The sad part is that most application developers don't really understand<br> POSIX I/O semantics and, so, many popular applications are vulnerable to<br> this.<br><br> (hint for those at home: write your content to a new file and rename it<br>
over the existing one; this is atomic, assuring you that the new or the<br> old file is there, nothing in between.<br><br> for bonus points include some recovery to determine if the new version<br> is complete and coherent, then offer to complete the task.)<br>
<br><br> > <a href="http://www.tummy.com/journals/entries/jafo_20041226_015752">http://www.tummy.com/journals/entries/jafo_20041226_015752</a><br><br><br>For a user who claims to care about data integrity this poster seems to<br>
have little actual clue: JFS is an exciting choice, at best, and<br> reiserfs...<br><br> Well, hey, the point someone starts talking about using reiserfs and<br> data integrity being important to them you can more or less know they<br>
don't really understand how data integrity is achieved.<br><br> reiserfs (3) has significant issues, many of which are performance or<br> data integrity related, and is close to impossible to recover if<br> /anything/ goes wrong.[2]<br>
<br> Regards,<br> Daniel<br><br> Footnotes:<br> [1] Their symptoms were completely different, much nastier, and fairly<br> identifiable. Zero length or null-filled files were not among them.<br><br> [2] ...or you happen to store anything that looks like a reiserfs<br>
filesystem inside them when you run the fsck tools.[3]<br><br> [3] This is highly amusing to me as I recall the excitement when the<br> developers announced a library version of reiserfs intended as a<br> "compound document" format for applications to use, delivering the<br>
same performance as the file system they were stored in...<br><br><br><br><br><br> --<br> ubuntu-server mailing list<br> <a href="mailto:ubuntu-server@lists.ubuntu.com">ubuntu-server@lists.ubuntu.com</a><br> <a href="https://lists.ubuntu.com/mailman/listinfo/ubuntu-server">https://lists.ubuntu.com/mailman/listinfo/ubuntu-server</a><br>
More info: <a href="https://wiki.ubuntu.com/ServerTeam">https://wiki.ubuntu.com/ServerTeam</a><br></blockquote></div><br>Hey,<br> Thought I'd share my experiences with reiserfs...<br> I'm using reiserfs on my mythtv box with a 4x400GB software raid5 array (~1.2TB usable) and it has been ok, but also unstressed so I won't go as far as vouching for it in a production environment. It's strength seems to lie in large numbers of small files rather than the large audio/video you're using.<br>
On the recovery side though, I was fiddling with the underlying lvm & md and managed to bork the system. I rebuilt the whole thing with the exact same parameters as I used originally and ran the reiserfs recovery tool to find it pulling files out of my (reiserfs formatted) VM images as well as the files actually in the fs. I ended up getting back _most_ of my data and had backups of the vms, so it wasn't a complete loss. I think the tried and tested 'just works' of ext3 would probably be a better choice in a potential recovery situation.<br>
My new place has brown outs during almost every storm and I've yet to invest in a UPS, the system has so far come back up without issue.<br> <br>cheers,<br>Owen.<br><br>-- If it aint broke, fix it 'till it is. --<br>