I'm trying this query here and on the VMWare forums. The MD3860i has dual active controllers, each with 2 iSCSI 10g ethernet links.

Question: how does multipathing in ESXi 6 work with this? Is any special setup or best practises required?

Reason: Each RAID disk group and LUN within the group is owned preferentially by one of the two controllers. Each of the 4 iSCSI ports has its own IP. Therefore multipathing access needs to be smart enough to choose the two correct IPs on a per LUN basis (LUN owner controller). Choosing the wrong IP (other controller) still works (via an internal pathway I guess) but at something like a 7:1 performance hit according to fio tests I've been conducting.

I do not see any special MPIO driver pack for the MD3860i SAN (unlike the EQLLogics which did have a special MPIO driver).

Is this something that ESXi figures out, or is it helped by the PV MD vCenter plugin?

On an aside, just noticed the vCenter plugin is only available for ESXi 6.0, not showing for 6.5 - just wondered if anyone else had noticed that?

 

Cheers - Tim

 

PS for our needs, the MD3860i is otherwise a good  choice - populated with 44 mix use 960GB SSDs arranged in 2 RAID6 disk groups and accessed by 4 hosts, I am seeing performance figures of upto 19k IOPS (4k blocks, total over all 4 hosts) and the ability to saturate all 4 10g links in an ideal test using random read/writes with 66% reads (which reflects our workload) - for a small unit it is very nippy.