DRBD - nodes with Dissimilar Hardware/Storage supported ?


this is a homework type question

we have dissimilar hardware on both nodes, one(Primary server) is Physical Machine with the partitions to be protected on reall/physical Hard Drvives, while the other one(Secondary) is a VMware ESX virtual machine, having file based disk storage.

We are interested to protect(via DRBD) /oracle file system.

on primary server we have a partition/filesystem named /oracle of size about 1.8 TB, while its usage is only about 400 GB.

On secondary machine which is a VMware ESX based virtual machine, we only have 1 TB disk space available for /oracle.

As /oracle file system is only consuming 400 GB on primary server, but the actual size of /oracle file system is 1.8 TB, and we can create /oracle on secondary node of about 1 TB only, therefore we are considering to use “thin provisioning” for /oracle on Secondary node.

such a setup works/supported ?


From the DRBD roadmap (http://www.drbd.org/home/roadmap/)

Ideas, not yet planed for a specific release:
Offer an improved resync mode, that deals gracefully with thin provisioned storage. Currently a checksum based resync already has this property. The improvement will be a special mode, that just does not rewrite blocks containing only zeros.

As far as I understand the current resync will always write all blocks which would break thin provisioning.

Best regards