[vox-tech] fsck, badblocks, defrag, and hd weirdness

[Peter Jay Salzman]

On Sat 08 May 04, 11:57 PM, Mark K. Kim <lugod@cbreak.org> said:
> On Sat, 8 May 2004, Peter Jay Salzman wrote:
> 
> > so my workstation has been closed for 1-2 weeks.  it's been much quieter
> > without gaping holes, but it has also been hotter.
> 
> Perhaps your old system was noisy because the fans were getting old?  My
> system recently started making some noises so I just replaced the
> problematic case fan.  All is back to quietness.  BTW, I have an aluminum
> case.
 
these are actually new fans.  the old ones were REALLY noisy, and
finally died.

i have an aluminum case for lucifer, but not satan.  i really love it
(aside from the fact that it has sharp edges -- it's actually made me
bleed).  wish i could remember what make/model it was.  i remember it
being dirt cheap.

> > last night, i left bittorrent running.  this morning, i woke up and saw
> > "I/O errors" in all my xterms.  i killed X, and saw "I/O error" in all
> > my consoles.  i had no prompt.  it just kept going "I/O error" over and
> > over.  here's what i did:
> >
> > 1. sync'ed, remounted read-only, and rebooted (alt-sysrq-s, u, b).
> > 2. at boot, hdc generated an "end of device" error.
> 
> What do you mean *hdc* generated an EOD error?  When did the error occur?
> (before POST, during POST, during Linux kernel loading, or during
> startup?)
 
while the kernel was detecting hardware.  kernel was already resident,
and the init scripts hadn't started yet.

> > 1. it *appears* that the drive overheated.  i've never heard of drives
> >    overheating.  but then again, i'm a hardware enthusiast.  not guru.
> >    has anyone heard of non-permanent drive failures due to over heating?
> 
> I've seen computers work after cooling down and not having any further
> problems when kept cool.  Don't think I've seen such problems occur due to
> hard drive problems.  But I can certainly see how hard drives getting hot
> can warp the drive casing and put stress on the platters and prevent data
> from being read properly without actually damaging the data on them.  But
> then... how important is the data?
 
not terribly. it's almost all music, videos, p2p stuff, doom maps, quake
3 maps, linux distro iso's, audiobooks, instructions on how to grow
magic mushrooms and sea monkeys, project guttenberg copies of collected
works by kafka, poe and lovecraft, pdf files of very old and very
classic dungeons and dragons modules, etc.

not terribly important.  but it took me a long time collect that stuff.
i'd be sad to see it go.

i have my mp3 collection backed up from about a year ago.  as for the
other stuff...  how exactly do you back up 80GB other than getting
another hard drive?  mp3's and video files don't really compress down
very much...

i just bought a DVD writer.  but even at 4.6GB...  they just announced
two layer DVD writers for the + format.  that would be more like it.
too bad it'll be out of my price range for a few years.   :-/

> > 3. i've never used badblocks before, but i figure it might be a good
> >    thing to do.  i did a test run on a smaller partition on a different
> >    drive.  here's the output:
> >
> >    lucifer# fsck -c /dev/hdb4
> >    fsck 1.35 (28-Feb-2004)
> >    e2fsck 1.35 (28-Feb-2004)
> >    Checking for bad blocks (read-only test): done
> >    Pass 1: Checking inodes, blocks, and sizes
> >    Pass 2: Checking directory structure
> >    Pass 3: Checking directory connectivity
> >    Pass 4: Checking reference counts
> >    Pass 5: Checking group summary information
> >
> >    /dev/hdb4: ***** FILE SYSTEM WAS MODIFIED *****
> >    /dev/hdb4: 18157/3112960 files (4.9% non-contiguous), 3130565/6221171 blocks
> >
> >
> >    it's unsettling that the filesystem was modified, but fsck made no
> >    mention about what got modified.  does anybody have any ideas about
> >    what exactly fsck modifies when it doesn't give you a reason?  that's
> >    really a rotten thing to do.  "dume2fs -b" doesn't report any bad
> >    blocks.  so what got modified?
> 
> Did you unmount the system first?
 
yeah.  try it on your system:

   fuser -k -m /dev/somepartition
   umount /dev/somepartition
   fsck -f -ck /dev/somepartition

i bet you'll get the same message.

> > 4. fsck reported that hdc2 is 30% non-contiguous.  that sounds like a
> >    lot to me.  i'm not going to do anything until i either regain
> >    confidence in this drive or replace it, but i was wondering if
> >    anybody here has any experience using e2defrag.
> 
> Looks fine to me but only because I come from FAT background (100%
> non-contiguous isn't unusual... =P)
 
really?   ok.  i'll take your word for it.  30% sounds like the hard
drive will have to perform a long seek on 3 out of 10 files sitting on
the drive.  that sounds like a border line to me.

> > 5. under windows, how is it that programs like scandisk and defrag can
> >    do their jobs without either umounting or remounting read-only the
> >    partition in question?  programs like fsck and e2defrag warn of
> >    "severe filesystem corruption" if you try to do this.
> 
> Does scandisk run under Windows?  I think it runs under DOS, in
> non-multitasking environments only.  I've seen it run a lot before Windows
> runs, under DOS, with disk-caching turned off, and no disk writing done to
> the FS.  Pretty much like accessing the disk as read-only or in unmounted
> state.

i don't think so.  i'm no windows expert (actually, my job is making me
one) but you can web browse while scan disk is running.  you can play
quake III while defrag is running.  at least, under windows 95/98 you
could.

the worst that would happen is that the progress meter would continually
go back to 0%.

> Defrag defrags the FS as much as it can, and when it detects that the FS
> is modified (a program writes to it, cache is about to be flushed, etc.),
> then it starts defragging from the start again.  It's really really
> annoying and it takes enormously unnecessarily long time to run.  But
> going through an already defragged portions of the HD is faster when it is
> read the second time since no clusters are moved (only verified that is
> contiguous.)
 
right.  that's what i was talking about above.

> FAT is a very... interesting FS... =)
 
you can _not_ make an statement intriguing as that one and not explain
it.   ;-)

> Anyway, I highly recommend you get some hard drive fans installed.  After
> realizing how hot hard drives get these days (not just an experience from
> my HP system, but I also read an article about it not too long after my
> experience) I realized hard drive fans are necessities, not just optional
> accessories anymore.

i think you're absolutely right.  that's what i'm going to take from
this experience.

which also means that "4 packs" of "y splitters" will also be
necessities too.    ;-)

pete

-- 
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