3ware 9550sx as a HBA


Mar 20, 2012
hei. Im about to build a new nas with some spare parts:
Supermicro rack case with 11 slots for 3,5inch
Bought a used 3ware 9550sx-12ML on ebay since i had good experiences with 3ware from before.

After googling a bit i found a bit on the issues with todays "cheap" drives and disconnects etc.

My question is: Does anyone know how the "single-drive" mode on 3ware controllers work? Will it work as a HBA and let the OS do "all" the work (disconnect timeout handeling etc) if i use md-raid on centos or zfs on solaris?

br TE
I was playing with a 9500 and a 9550 and single drive mode with FreeNAS for a bit. It does present the drives out to the OS for consumption, but still writes a little metadata to them since technically each one is still in an array, just a single drive array. Beyond that, the speed was definately not spectacular. Adequate-ish speed, I guess. I snagged one of the Rackable 3u 12bay boxes from fleabay and have done a bit of testing trying to find the best iSCSI platform for my home ESXi lab. With 12 250's in in singledrive mode presented to FreeNAS 8 or OpenFiler 2.99 configured in a ZFS array versus the 3Ware hardware raid 50, the speed was the same, slow... As a comparison, I think I'm going to snag an Supermicro 8 port Sata card and try that with ZFS as a comparison.
Set the controller to export unused drives as JBOD, and there will be very little interference from the controller logic.

You will still have to use the 3ware options for smartmontools, but other than that they appear as (mostly) normal drives to the OS.
Sorta-kinda. I reworked my FreeNAS box last night to test that theory. FreeBSD would only recognize the drive if I exported them in Single-Drive mode. It would NOT recognize the automatic JBOD Export. Windows 2008 R2 did once I loaded the driver during install. I had originally installed FreeNAS to USB, so I botted that back up and did a few tests with a ZFS pool of 12 x WD2500YYS created in SingleDrive mode and created an iSCSI connection to my ESXi box. Under single drive config, it seems like it's supplementing with the Cache on the card. The 4 VM's I installed to that datastore, are definately snappier than the were before. I don't know about overall throughput yet, but in the short term it seems like a quick improvement.
I've got a 3ware card from that series in a 12 disk Raid-5 and the writes are slow as hell. on the order of 100mbt. But.... I read from it far more than i write to it so it's not a huge deal. The read speed is more than enough to saturate a 1gbt ethernet connection.

I doubt that answered any of your questions but just had a little experience to offer on the card. :p