[linux-lvm] Re: Recovering from disk failure

[Måns Rullgård]

mru at users.sourceforge.net (Måns Rullgård) writes:

>>> Recently one of two disks in a volume group crashed, and I can't read
>>> it at all.  Now, some LVs are entirely on the disk that survived.  Is
>>> there any way I can just disable the broken LVs and continue using the
>>> complete ones?  I'm using device-mapper and LVM2
>>
>> Read the description of '--partial' on the lvm(8) man page.
>> e.g. (lv|vg)change -ay --partial
>
> I should have read the manuals before mailing.  However, I still have
> some questions.  Some LVs were split between the two disks.  With the
> --partial option, it won't let me see them at all.  Can I do something
> to get just read errors, or zeros, or whatever for the missing
> sectors?  I could of course do some manual work with dd, but an
> automated method seems easier.

I figured it out, after reading some source code to determine that the
dmsetup man page is incorrect.  It tried to tell me that the
"target_type" for an all-errors mapping is "io-err", when it is in
fact "error".  Someone should fix this.

-- 
Måns Rullgård
mru at users.sf.net