I'm in the market for an entry-level multi-drive raid solution (with 4 drives or so)
I spoke with a tech person at Other World Computing (they always seem knowledgeable and helpful).
I was planning on going for one of the La Cie Raids with 4 or 5 drives, but the tech person was steering me towards the OWC brand Raid. She said it's cheaper than the La Cie, and just as good.
With four drives, the bottleneck could very well be USB 3.0 - in reality its speeds are way below theoretical limits of 5Gbs and closer to half that, utilizing less than 50% of potential performance of four drives. Thunderbolt will be much faster here, provided the box has a decent RAID controller.
-- Alex Gerulaitis | Systems Engineer | DV411 - Los Angeles, CA
Do you mean RAID 1 among four disks creating two mirrored RAID sets; or do you mean a single RAID 10 set?
With USB I'd steer clear of software raid1. The 4Big may very well be software raid1 because it's not listed, meaning it would be done through Apple Disk Utility. The difference is the mirroring with software will require two streams, consuming twice the bandwidth to the device. Whereas when implemented internal to the attached storage device (often hardware RAID but could still be software running within the box) it's a single stream to the attached storage, and the device itself does the mirroring (again internally).
In theory with a 4 disk raid10 you could have up to 4x read performance (which depends on a less common layout, that also incurs a write performance hit), more typically it's 2x the single disk read performance. With drives capable of 150MB/s transfer rates, for sure 4x hits the theoretical USB 3.0 bandwidth and busts the practical max. Even 2x, at 300MB/s is over the typical real world max transfer rate of 200MB/s of USB 3. So really you need to compute your present and future bandwidth requirement to know whether or not you need more than this. Just because the expected real world USB limit is less than Thunderbolt, doesn't mean it's disqualifying for your use case.
Regarding a software RAID, i'd like to test the following setup:
taking 2 Guardian Maximus enclosures running RAID-1 internally, and putting them in a Software RAID0. This would theoretically get by the USB3 speed limit because each of the two USB3 connections would be running at a single drive RAID1 speed. It would then depend on the USB3 controller in the computer and the software for the RAID0.
I'd like to try this on my 2009 Mac Pro with the CalDigit USB3/eSATA card. This should work with the OP's MacBook Pro, but it would be interesting to see if the USB3 controller in the MBP would be a limiting factor.
Additionally, I'd test the enclosures set to JBOD (if that's possible), and test just one disk in each enclosure with software raid0. Then rebase with enclosures set to raid1, and then remake the software raid0 and test again. This gives some idea of the raid1 write hit and read gain. This would be workload independent, so the test method doesn't matter as much.
The other test(s) would be changing the raid0 chunk size, which I think with Apple software raid defaults to 32KB which is almost certainly too small for video editing use case. I'd test the default, but also 512KB and then whatever the maximum offered is. However, for this test, it's important to get test method to mimic the actual workload or the results will lead to the wrong conclusion.
And the repeat all the tests with eSATA!
When it comes to troubleshooting, a drag with USB is that most bridge chipsets don't pass through SMART commands, and even with those that do OS X lacks the necessary driver support. Yes it's only ~60% predictive of failures, but in cases of unexpected behavior, getting the full list of SMART attributes can sometimes be useful by suggesting sources of problems well before the simplistic pass/fail metric reaches the manufacturer defined threshold.
Hi all. I hate to admit that I got a little lost in the technical lingo of some of these post..a bit over my head.
Perhaps if I rephrase the question more simply, it might be clearer what I'm asking.
I've been using Guardian Maximus 2-drive RAID 1 setups for a while.
I want to graduate to a similar RAID with more drives that I can swap in and out (so I just have one big enclosure, rather than so many smaller boxes).