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

[Jeff Rollin]

Hi Boyd.

On 28/03/07, Boyd Stephen Smith Jr. <bss03@××××××××××.net> wrote:
> On Wednesday 28 March 2007, "Jeff Rollin" <jeff.rollin@×××××.com> wrote
> about 'SOLVED: Recover from LVM errors? (Was: Re: [gentoo-user] Help -
> system reboots while compiling)':
> > Ignore the following if you don't like minirants.
> (My reply probably needs the same disclaimer.)
>
> > 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.
>
> By that definition, no filesystem I can think of is "mission critial", they
> will all withstand some damage and still let your system come up.  /var is
> *at least* as important as /usr -- I can easily recover the contents
> of /usr in case of critical failure, but reconstructing /var is damn near
> impossible.  Also, /usr can generally be very useful with just r/o access,
> while /var needs to be r/w to fill it's role.

That's true.

>
> Also, forcing a mount of a damaged filesystem is asking for trouble.
> Dangling inodes (or similar) can cause cascading failure; at best some
> processes will read garbage and crash (or, ideally, "magically" recover)
> at worst good data on the disk will be overwritten with bad. File locks on
> a damaged filesystem are meaningless since two files (not simply two
> dirents like with a hard link, but two unrelated files) might share disk
> sectors.

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.

>
> The system should definitely refuse to mount damaged file systems by
> default or *at the very least* mount them read-only.

Agreed, definitely.

I wouldn't mind and
> interactive prompt to force mounting a damaged filesystem, but I'd need a
> way to turn that off for unattended systems.
>
> --
> Boyd Stephen Smith Jr.                     ,= ,-_-. =.
> bss03@××××××××××.net                      ((_/)o o(\_))
> ICQ: 514984 YM/AIM: DaTwinkDaddy           `-'(. .)`-'
> http://iguanasuicide.org/                      \_/
>
>

Jeff.

-- 
Q: What will happen in the Aftermath?

A: Impossible to tell, since we're still in the Beforemath.

http://latedeveloper.org.uk
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