My company has only a single storage box (SuperMicro hardware + chassis with a LSI raid card and 12 SAS 7.2k drive) in its current setup. It runs on linux and we hook it up to our fileserver via iSCSI. We can't afford a high-end SAN. While it has redundant parts in it (dual PSUs, RAID 10), I would like to add in a secondary box for replication purpose.
I'm considering the following two options to replicate the data from node 1 to node 2
Using DRBD to create a network based mirror. Active/passive. Node 1 remains as iSCSI target, and setup drbd underneath it so that data can be replicated to node 2. If node 1 goes down due to networking problem, I suppose the recovery is much faster since we don't have to resync the data from node 2 from scratch once node 1 is plugged back into the network.
Setup both nodes as an independent box. Each of them will expose a LUN to our MS server 2008 FS. From there, I will setup a windows based software mirroring using both LUNs. My concern is that, in the event one of the LUNs drops out, we will have to rebuild the entire array, which will be very time consuming as we have about 6TB of data to copy over.
To me, both serve the purpose well, but the DRBD option seems more complex to manage. Please advise on the pros and cons.