I use a HP Microserver N40L for my home NAS, which run the fantastic FreeNAS operating system and 4x 2TB drives in a RAID-Z2 configuration. I wanted to back up the NAS onto an external drive, with the great feature that is ZFS snapshots.
I started looking at 4TB external drives. The N40L has eSATA and only USB2.0, so I thought that eSATA was my only real option. I quickly learned that eSATA is fast becoming a dead technology, as USB3.0 takes over.
The pure eSATA drives seemed to top out at about 1 or 2TB. The ones that go up to 4TB – the cheapest ones are pure USB3.0. The ones (from Lacie and others) that have eSATA, USB3.0 and FireWire are very expensive, and it is actually cheaper to get a USB3.0-only 4TB drive plus cheap USB3.0 controller card, than it is to get one that supports eSATA. My decision was further solidified by the fact that the new “Gen8” HP Microservers don’t even have eSATA. Buying a USB3.0 controller card became a no-brainer.
I went for a Astrotek 2 Port External / 1 Internal PCI Express USB3.0 Card from the fine folk at Scorpion Technology. The specs as copied from Scorpiontech:
Chipset : RENESAS 720201
PCI Express Base Specification 2.0
2 x USB 3.0 Downstream Port
1 x ICC USB 3.0 (2 x USB 3.0) Internal Downstream Port
1 x ATX Molex Power connector
Compliant with USB specification 3.0 rev. 1.0 compliant
Max. 5 Gb/s transfer rate per port
Supports Super-speed (5 Gb/s), High-speed (480 Mb/s), Full-speed (12 Mb/s), & Low-speed (1.5 Mb/s)
Supports USB 3.0, USB 2.0 & USB 1.1 devices
Compliant with Intel xHCI (eXtensible Host Controller Interface) specifications Revision 1.0
Supports USB Battery Charging Specification Rev. 1.2
Supports PCI Bus Power Management Interface Specification rev. 1.2
Supports USB Wake-up function(total max. 5V/600mA)
1.5A MOSFET Power Switch Protection & Over-current sensing for each port
Supports Hot Swap, Plug & Play
Drivers support Windows XP, Vista, 7, & Server 2008 Release 2 (x86 & x64)
Linux Kernel 2.6.31 native support
Low Profile support
I’ve bolded the items that appeal to me the most.
The Renesas 720201 seems to be one of the best performing USB3.0 controllers, according to a VR Zone review.
Since FreeNAS is built on FreeBSD, any spec sheet that lists an open source OS is good news. I was thus hopeful it would work in FreeNAS.
I plugged in with FreeNAS 8.3 and got no joy. I saw that the card was recognized by the BIOS and was given an IRQ, but it was dead in FreeNAS. I downloaded a copy of the new FreeNAS 9.1.0RC2 and to my pleasant surprise found that it worked perfectly. Since I’m not ready to upgrade to beta code for my NAS, I’m in for a bit of a wait until I can use my external USB3.0 drive, but shouldn’t take too long.