[DRBD-user] DRBD 0.7.23 and MD corruption

Lars Ellenberg lars.ellenberg at linbit.com
Wed May 23 18:26:53 CEST 2007

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

On Wed, May 23, 2007 at 12:16:25PM -0400, Ross S. W. Walker wrote:
> Lars, et al,
> I was wondering if a block storage device, which could exist on an MD,
> were to be fully utilized before it was incorporated into a drbd
> replication scheme would it also suffer from corruption.
> Why I ask, is that I have a bunch of volumes used as iSCSI targets
> that I am planning on replicating in the future, but are in production
> today and wanted to know if it is safe to create replicas of these,
> using a separate LV for meta-data?

if you have the drbd meta data on a separate lv,
DRBD is completely "transparent",
comparable to a dm-linear mapping over the full device.

so it "should just work",
and it does so for us, all the time.

but, you know, murphy and "shit happens" ...
and the issue with the "READA failing without error on MD raid5",
mentioned earlier in this thread is a real one.
dm-crypt has suffered from it, and so would drbd, probably,
when stacked directly on a md raid5 array.

we will double check and realease a workaround.

note that typical usage is unaffected, though.
[md is a pv, and drbd resides on an lv, so on dm-linear]

: Lars Ellenberg                            Tel +43-1-8178292-0  :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe    http://www.linbit.com :
please use the "List-Reply" function of your email client.

More information about the drbd-user mailing list