1/11    A power outage caused my LINUX computer to crash and fsck can't fix
        the disk because of a bad superblock.  I tried everything in
        the fsck and e2fsck and nothing fixes the bad superblock.  Any
        suggestions for fixing things or partially recovering data?
        \_ superblock is repeated every 5000 blocks or something like that.
           you can use some tool (something like mkfs... ask MOTD for detail)
           to get a list of it.  Chances are, you will have a working
           superblock.  Then, you use fsck manually specify the superblock
           you just found.  I personally has gone though this many times, and
           felt that Linux is a lot more fragile than I would like because
           of this reason.
        \_ Ok, not trying to start another FreeBSD vs Linux flame war but
           somebody has to ask.  Did Linux people wrote they own filesystem
           or did they borrowed heavily from *BSD?
        \_ sometimes, mke2fs creates backup superblocks? did it?
           also, I think the ext3 file system is more durable (next time)
           \_ fsck -b 32 (see man pages) Or use a journalled file system
        \_ Sometimes you can mount bad filesystems read-only and extract
           data.  I was able to do this on a FreeBSD partition with hard
           errors and extract a fair amount of data before the disk
           stopped responding altogether.  YMMV.
        \_ Just wondering, were you using ext3 or any of other journaling
           file systems at the moment?
        \_ Oh dear, another person learns the hard way that linux isn't
           production quality.  Eventually you kids will figure it out and
           move on to real OS's with real file systems or you'll stop putting
           useful data on bad OS's, at least.  No one ever think it'll happen
           to them....  Ext2 is a POS.  Ext3 is a POS+bad journaling.  Do not
           trust any valuable data on these filesystems.  Valuable means
           you wouldn't /bin/rm it yourself.  My cheap ass employer puts many
           many terabytes of very valuable data on ext2 with no backups.  We
           lose data all the time on those systems but not on the real ones.
           \_ My brother-in-law started a new job, sort of night-watchman
              for their computer systems.  A power-outage caused
              crashes (UPS wasn't regularly tested) Only later did they
              find data had been corrupted.  Something to do with the
              type of cheap linux disk and cache flushing or something.
              \_ is there a semi-formal discussion of this anywhere?
                 something you can point the money/management people in
                 company to?
           \_ Please give some examples of better filesystems.
                \_ These people sound like FreeBSD bigots.  I bet they have
                   UFS in mind.  Still, not even UFS will save you from a disk
                   crash.
                   \_ No, but ext2fs at least is by default mounted async b/c
                      of the slow metadata updates (rm -r/tar x taking forever)
                      Async + power outage = major fs problems.  If you mount
                      sync, your performance goes to shit.  Ext3 and FFS +
                      soft updates both solve this problem.
                  \_ No.  I wrote the "Oh dear" comment.  I don't have *any*
                     Freebsd systems.  You sound like a linux zealot defending
                     your beloved POS at all costs with no sense.  Ext3 is a
                     huge joke.  When you take a POS ext2 system which will
                     lose data on an idle system and "bolt on" a crappy wannabe
                     \_ Please give examples of better filesystems
                     pseudo-journaling system like Ext3 you don't get a JFS,
                     you get a crappy ext2 FS with crappy bolted on journaling.
                     His disk was probably bad *before* the disk crash and he
                     didn't know because he hadn't power cycled in months.  He
                     likely didn't have a disk crash from the power outage. He
                     probably had an ext2 barf all over his disk earlier and
                     it didn't show until he needed to get that super block.
                     \_ Ok, I'll bite. What makes ext3 a "pseudo journaling"
                        file system and why its journaling is considered as
                        "crappy bolted on journaling"?
                     \_ Please give examples of filesystems better than etx3
                        \_ reiser?
                        \_ vxfs.  wafl.  xfs (real xfs)
                        \_ if you're talking about Linux file systems, ext3
                           is the safest choice and it is "blessed" by the
                           leading kernel developers. I disagree with the rants
                           about ext2/ext3 here. We used ext2 at work. We had
                           power outages. Did we have to wait for hours for
                           fsck to complete? Yes. Did we lose any data? No.
                           Ok, maybe we were lucky.  Now we're using ext3. We
                           had no problems with it whatsoever. We never had
                           to fsck a file system, never lost any data. And
                           by the way, vxfs is available on Linux too,
                           as a part of Veritas foundation suite, if you'd
                           like to use a "real" file system..
                           \_ Thanks, I like your practical viewpoint.
        \_ If your data is important to you, you will use RAID. Disk failures
           happen under any O/S and there is nothing you can do about it
           but use redundancy. Anyone who tells you otherwise is full of crap.
           \_ I wouldn't stop at RAID.  You need to backup your RAID too.
              A single RAID box could be taken out by a power surge.