On Thu, Oct 9, 2014 at 11:43 PM, John R Pierce pierce@hogranch.com wrote:
Most people forget that DRDB is a 'clustered' storage that creates a new block device on top of existing block devices, over the network.
There are issues like SPLIT BRAIN and a possible data inconsistency, should there be multiple network timeouts, congestions (since it is all network based) etc. This may not be the best solution for your problem!
those are potential issues with ANY high availability clustering solution that need to be carefully engineered around. HA clusters commonly use fencing technology to prevent split brain, dedicated network adapters just for replication, and redundant connections for status monitoring, etc.
And you still need backups. Other things besides hardware failures can wipe your data and with mirrors/clusters, software or operator errors will take all the copies at once.