I was wondering if there was any way to replicate the functionality of the HP StorageWorks P4000 Virtual SAN Appliance using open source tools?
Basically the HP VSA lets you replicate in the same way DRBD does but it lets you use both of the block devices in a RAID 1 fashion so you can read data from both the local storage and from the replicated storage on the other server.
When I've tested DRBD I've used it in active/passive so if i have RAID10 and DRBD sitting on top of it in both servers, one server does all the work while the other us just receiving the replicated block data in prep for the failover. I'd like to get test using both to read from at the same time, so if i had 30 XEN guests on one server the load would be spread over the storage on two or more physical servers.
Hopefully that makes some sense. Any pointers would be most appreciated.