[linux-lvm] Simulating LVM Mirror Failure and recovery

[Lupe Christoph]

On Thursday, 2009-04-16 at 15:47:07 +0530, yogeen honnavar wrote:

> dd if=/dev/zero of=/dev/vg1/lv1 count=10

> 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.

Apart from the problem with the of= parameter that was already pointed
out - why do you assume writing *anything* *anywhere* would simulate a
mirror failure? The most you do simulate with that is mirror
*corruption*.

To simulate a failure, you have to somehow disable a drive. Unplug a
cable, force it to spin down (assuming that it is not automatically spun
up again, I dunno), change the zoning, whatever is needed to prevent
access to the device.

> can anyone please let us know the correct way to simulate lvm mirror failure and recovery.

Depends a lot on your hardware. E.g. the system I use for testing are
about 400 km away, so I'd rather not unplug anything...

HTH,
Lupe Christoph
-- 
| There is no substitute for bad design except worse design.                   |
| /me                                                                          |