I'm setting up a server with and SSD as the primary drive, and would like to duplicate the data onto a cheaper drive as a block-level backup (à la RAID1).
Since I don't want to hobble the performance of the SSD I was considering setting up DRBD with asynchronous mirroring so that changes get queued up for the spindle drive and eventually synced up once IO permits.
But I'd like to know if anyone has tries something like this and if there are any "gotchas" to pay attention to. Alternately, if there's a better technology to solve the same problem, please share.