Re: SOLVED: Recover from LVM errors? (Was: Re: [gentoo-user] Help - system reboots while compiling)

[Boyd Stephen Smith Jr.]

On Wednesday 28 March 2007, "Jeff Rollin" <jeff.rollin@×××××.com> wrote 
about 'Re: SOLVED: Recover from LVM errors? (Was: Re: [gentoo-user] Help - 
system reboots while compiling)':
> > > 1. Frankly, I'm not impressed with Linux in this case*. /var is not
> > > a "mission critical" filesystem in the sense that if it contains
> > > errors, it can still be mounted and the errors don't necessarily
> > > mean the system won't come up.
> >
> > [F]orcing a mount of a damaged filesystem is asking for trouble.
>
> It IS a bad idea, but it's not like I "forced" a mount; the system
> came up normally and functioned normally until it hit a damaged inode,
> whereupon it crashed with nary an indication of what had gone wrong.

Ah, yes, that's a problem.  What filesystem are you using?  I was fairly 
sure ext2/3 tries to detect damage (even while r/w mounted) and force a 
r/o re-mount or unmount.  [Not that that couldn't cause a freeze or 
reboot, but at least it's conservative.]

Reiserfs (and possibly others) is quite stupid, at least in this regard.  
After the filesystem is mounted it performs basically zero sanity checks, 
and always assumes the data provided by the block device is complete and 
accurate.  It can't handle a slowly failing HD, and will almost assuredly 
silently corrupt data on such a device.  This is one of the reasons some 
people strongly recommend against reiserfs.  I still use it, but my 
important data is on RAID6 (underneath LVM), so I can be fairly certain 
the data received by the filesystem is good.

/me is looking for a new favorite file system.

-- 
Boyd Stephen Smith Jr.                     ,= ,-_-. =. 
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