RN3220 / RN4200 Crippling iSCSI Write Performance

So to clarify after the above replies:

• I'm ONLY using fixed size LUN's on the RN's
• I've tried both fixed and dynamic VHDX's, there's virtually nothing between them stat wise
• Sync writes are disabled
• Copy on write isn't used anywhere
• I agree, you should never team iSCSI, that's page 1 stuff. I've tested with single channel or MPIO in dual channel

Based on the previous comment on RAM from nxtgen, I pulled some DDR3 1866 dimm's from a server temporarily and replaced the DDR3 1600 dimm's. The initial test set it to 12GB, single channel due to 3 dimms.

The second to 16GB, all dimm's identical, dual channel

This is the RAID6 array again, with nothing else on it, still running 6.9.0 and local iSCSI, not CSVL. I repeated the test with MPIO on and off. Writes get dented slightly in no MPIO mode, but that 4MB sequential number just won't move up on these arrays.

As you can see, a whole lot of nada. Running top in SSH shown that with enough activity, the system will claim the full amount for cache, leaving about 400MB free every time.

Rebooting the NAS, booting the VM and running Anvil, leave the NAS with about 4.4GB RAM used and the rest free.

I didn't screen shot it, but I put the array down to 4GB RAM, single channel and ran it again. The numbers were identical! No difference!!!

Copy a file to them over SMB or NFS and the arrays will saturate the link(s), no issues there. It's purely the iSCSI.