A number of you have indicated an interested in 200MB/s storage solutions for your Mac. You don't need faster but you don't want slower. We are in the process of testing some 200MB/s solutions but, in the meantime, we offer six things you should know.
1. AS DRIVES FILL, SPEED DROPS
With today's fast 7K SATA drives, all you need is two in a RAID 0 set to go 200MB/s or faster. However, keep in mind that as drives fill up, the speed drops to as much as half to 100MB/s. If you need to maintain 200MB/s no matter how full your volume gets, see points #4 and #5 below.
If you do decide to go with a dual drive enclosure, here we will be testing and reporting on soon:
- The CalDigit VR is a dual drive RAID 0, 1, and JBOD enclosure with removeable trays featuring eSATA, FireWire 800*, and USB 2.0 ports. It uses an external power brick.
- The OWC Mercury Elite-AL Pro RAID is a dual drive RAID 0 "sealed" enclosure featuring eSATA, FireWire 800*, and USB 2.0 ports. It uses an external power brick. This is the most aggressively priced of the bunch.
- The Sonnet Fusion F3 supports RAID 0, 1, and JBOD with eSATA, FireWire 800*, and USB 2.0 ports. It is a sealed unit but includes an integrated power supply.
- The FirmTek SeriTek/2EN2 dual bay hot-swap SATA enclosure with removable trays. It only has an eSATA port and only supports software RAID, but produces the best performance on the MacBook Pro using an ExpressCard/34 SATA adapter.
(* FireWire 800 port can be used for FireWire 400 with the correct converter cable.)
2. NOT ALL SATA EXPRESSCARDS ARE CREATED EQUAL
Most SATA ExpressCard/34 adapters for the MacBook Pro hit the wall at 128MB/s. Sonnet's Tempo SATA Pro ExpressCard uses a special Marvell chipset to achieve 200MB/s with Port Multiplier support. However, not all enclosures will achieve that speed with this card. And some Oxford based enclosures had problems with 2TB+ volumes, though the latest driver is supposed to fix that.
3. A MAC PRO DOESN'T NEED A PCIe SATA HOST ADAPTER FOR MORE THAN 4 DRIVES.
If you are wanting to connect an external SATA enclosure to your Mac Pro without messing with a PCIe host adapter, one easy way to do it is with the NewerTech eSATA Extender Cable. It enables you to harness the 5th and 6th SATA ports on the Mac Pro motherboard that are hiding behind the PCIe bay inlet fan.
We have used it to connect to various external SATA enclosures including all those mentioned in this article. Two caveats: a) You can't boot Windows from a Boot Camp partition from those ports, and b) hot swap is not supported.
4. YOU DON'T NEED A SATA RAID ADAPTER TO GET RAID 5
Some companies are starting to offer SATA enclosures that support RAID 5 in the box. One example is the Wiebetech RTX400H-QR that we will be testing in the near future. It also offers features like rugged carrying handle, tray free bays, and quad-interface. (Don't forget to enter their contest to win one.)
5. PORT MULTIPLIER ENCLOSURES CAN'T EXCEED 225MB/s
Port Multiplication (PM) is still very popular with users since one thin cable connects to up to five drives in the case of PM enclosures connected to PM host adapters. One of our favorites is the FirmTek SerTek/5PM. It's unique in that the installed drives connect directly to the backplane, reducing the chance of Electromagnetic Interference (EMI) that can cause data transfer errors. It also gives you the choice three cooling fan speeds and an alarm in case either the drives overheat or the fans fail.
Keep in mind, however, that no matter how many drives are connected to a single PM port or how fast the drives may be, the fastest trasfer speed will be around 225MB/s. However, that speed will be maintained no matter how full the drives get if you have at least four.
6. DON'T BELIEVE ALL YOU READ ABOUT DRIVE RELIABILITY
There is much debate on which brand and model of 3.5" SATA hard drive is the most reliable. We don't test for reliability. We can assure you that all brands of drives have the potential for failure. I have three suggestions: backup, backup, and backup.
We at Bare Feats Labs can speak to performance. Thankfully, Seagate has solved their hiccup with the 1.5TB Barracuda using firmware updates -- a drive we have found to be the fastest 7200rpm SATA drive for large sequential transfers. The Samsung Spinpoint F1 is the second fastest. For small random transfers, the WD Caviar Black 640G and Blue 640G are the fastest 7K SATA drives we have tested.
As for 10K SATA drives, the WD Velociraptor 300G "backplane ready" is without equal. And when it comes to 15K SAS drives, we like the Seagate Cheetah 15K.6 450G the best.
