[DRBD-user] How long will the primary DRBD continue to run without a secondary?

Robert Altnoeder robert.altnoeder at linbit.com
Mon Jun 18 10:20:21 CEST 2018

On 06/15/2018 02:07 AM, G C wrote:
> I know the secondary is the DR and the primary keeps track of what is
> changing but how long can it continue to run in this state before it
> will cause it to crash or not be writable any longer?  I would gather
> that at some point it would cause a lack of resources to write the
> changes to but I'm not sure and can't find any information related to it.

Indefinitely, because it does not keep track of the changes themselves,
it only tracks which blocks have changed. This information is kept in
the DRBD metadata, which is preallocated to be large enough to cover all
data blocks (requiring one bit per 4096 byte data block on the storage
device in DRBD's bitmap, plus some alignment, so the size of the bitmap
is approximately 1 / 32768 of the size of the storage device).

Best regards,
Robert Altnoeder
+43 1 817 82 92 0
robert.altnoeder at linbit.com

LINBIT | Keeping The Digital World Running
DRBD - Corosync - Pacemaker

DRBD® and LINBIT® are registered trademarks of LINBIT, Austria.

More information about the drbd-user mailing list