Re: [linux-lvm] Simulating LVM Mirror Failure and recovery

[Tomasz Chmielewski <mangoo@wpkg.org>]

vu pham schrieb:

>> as per the redhat guide this should result in mirror leg failure and 
>> any subsequent write activity to the mirror should convert the mirror 
>> into linear volume. but the output of lvs command still shows copy % 
>> as 100%. also data in filesystem of lv1 is erased and it is converted 
>> into read only filesystem.
>>
>> can anyone please let us know the correct way to simulate lvm mirror 
>> failure and recovery.
>>
>> thanks and regards
> 
> I think to simulate error failure you have to write to the underlying 
> devices, not the mirrored device. When you write to the mirrored device, 
> lvl1 in this case, data is mirrored so there is no failure at all. So I 
> think you have to dd to either /dev/sda3 or /dev/sdb3.

How will LVM distinguish between a valid and invalid copy in that case?

Are you sure that on reads, LVM will return data from the "good" copy, 
not the one you just overwrote with "dd if=/dev/zero of=/dev/sdb 
seek=xxx bs=1M count=10"?


-- 
Tomasz Chmielewski
http://wpkg.org