[DRBD-user] strange device problems after failover

Felix Frank ff at mpexnet.de
Tue Jan 11 15:39:52 CET 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On 01/11/2011 03:19 PM, netz-haut - stephan seitz wrote:
>>> Could anyone shed some light on what could be wrong? Thanks!
>> I believe I heard something about LVM being smart about aligning itself
>> to array stripes. If your stripe size changed, it may be possible that
>> LVM expects to find signatures at other boundaries now.
>> You may want to sync to another array with the original stripe size and
>> see if that works.
> Thank's for your suggestion, I'ld try this as a last resort. First I have to look for some spare 16TB...
> Do You really think, the stripe size of a hardware raid does matter to LVM alignment algorithms?
> I peeked into /sys and /proc but I didn't find any exposure of this value to the system at all.
> But anyway, thanks!

>From what I've heard (at DRBD Total no less), LVM can and will
interrogate your very RAID controller to find out about such details.
If this should proove to be the culprit, well - yay for Linbit training? :-)

Note that this makes an awful lot of sense. You don't want your generic
userland to concern itself with that kind of low-level storage detail,
but to LVM, this can become a performance issue.


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