Re: Corrupted/unreadable journal: reiser vs. ext3

[eazgwmir@umail.furryterror.org (Zygo Blaxell)]

In article <200302130522.35829.sam@vilain.net>,
Sam Vilain  <sam@vilain.net> wrote:
>But with disks, you can.  Mirroring aside, modern hard disks use S.M.A.R.>T. 
>technology which claims to be able to spot failures before they happen.  
>Many BIOSes will let you turn this feature on and off.  Of course I've 
>never actually seen it in action :-).

I have seen SMART work.  At 11:20:30 I had a disk fail, then smartd put this
in my logs:

	Nov  6 11:20:30 chlorine smartd: Device: /dev/hdb, Failed attribute: 3

Oh, wait, you said "before"...no, I've never actually seen that in
action either.

SMART does give you statistics on ECC recovery rates, temperature, number of
remapped sectors, etc. which can give you a hint, if you keep track of them
over time, when your disk is beginning to have more problems than it did have
when it was newer.  Maybe about 50% of failures can be predicted this way
(but you have no idea _when_ the failure will occur--this afternoon or next
summer?) it's little better than the MTBF rating.  The other 50% of
failures are predicted only after the fact.  :-P

-- 
Zygo Blaxell (Laptop) <zblaxell@feedme.hungrycats.org>
GPG = D13D 6651 F446 9787 600B AD1E CCF3 6F93 2823 44AD