Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Mon, May 10, 2010 at 03:09:57PM +0200, Katharina Haselhorst wrote: > Hello, > > I've a question concerning the truck based replication. Following > scenario: Host A is working with a device in primary role in > standalone mode. It is continuously writing data to the device. Host > B does not have any of the data and should be synchronized as far as > possible to the device of host A. > > According to the instructions on the drbd website, I do drbdadm -- > --clear-bitmap new-current-uuid resource, archive the device images > (including the metadata), send them to B and do a drbdadm > new-current-uuid resource. > > My question: Is it possible for Host A to keep writing between the > first command (with --clear-bitmap) and the archivation of the > device image? Yes. Starting with old uuid, possibly partially dirty bitmap. [A] Generate new uuid, clean bitmap. The now clean bitmap will be re-dirtied with everything that is written from now on. [B] Disk gets pulled, imaged, whatever. [C] Second new uuid generated. (*NOT* clearing the bitmap this time) This marks the end of the imaging/disk pulling. Bitmap contains everything that has been redirtied since [A] [D] bitmap continues to be updated. [E] Connect of image (from [B]) to current: normal bitmap based resync. Everything that has been re-dirtied since [A] will be resynced. > Or do I have to suspend Host A (at least the > application writing to that device) for that time? No. If you can minimize write activity between [A] and [E], you will have a minimal resync. -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed