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RAID Controller Shoot-Out
mikemuch writes "ExtremeTech has a comparison with benchmarks of three RAID controllers from Adaptec, LSI Logic, and Promise, and along the way gives you a little refresher course on RAID in general and why you want to use it: faster throughput, longer uptime, and improved data security. Motherboard RAID controllers do well when there's 'very little or no load on the CPU, I/O bus, and memory bandwidth. But with heavy traffic and processor loads, the limitations of the shared bus and the benefits of intelligent RAID's integrated IOP and memory cache have a more significant impact.'"
According to the OpenBSD i386 supported hardware website, out of the cards reviewed, only Adaptec and LSI cards are compatible with OpenBSD.
However, Adaptec has refused to provide documentation so that the OpenBSD project may improve the drivers.
"Note: In the past year Adaptec has lied to us repeatedly about forthcoming documentation so that RAID support for these (rather buggy) raid controllers could be stabilized, improved, and managed. As a result, we do not recommend the Adaptec cards for use."
Other *nix variants might support the Adaptec and Promise cards a little more, but the hardware fully supported by OpenBSD is generally well-supported across all *nix variants.
Out of the cards reviewed, only the one from LSI is worth buying. Adaptec may have a little support, but it's not a good idea to purchase any RAID cards from them until they start providing better documentation.
Ok, I realize it's a bad metaphor because you actually can throw a motherboard quite a distance. But here's another example of where things can go horribly wrong: How do they handle error conditions? On my desktop system, I'm running RAID-0 (with WD Raptor drives) for speed. Yes, I know what I'm doing (famous last words). No, I don't store any important data on my desktop (it's on a RAID-5 array on a server). Originally, I was using the Silicon Image 3114R on-board RAID controller included on my Asus A8N-SLI "Premium" motherboard. Eventually one of the drives died. The SI3114R responded to the problem by freezing and becoming unresponsive when a disk error occurred. Under DOS, Linux, or WinXP - the problem is not OS specific. The rest of the system works fine, but once it hits an error the SI3114R just stops working and returns nothing but errors to the OS. Now, since Asus doesn't update the SI3114R BIOS in their mobo BIOS updates (and I'm too lazy to hack my own), I don't know whether it's bad silicon, bad BIOS, or a bad design (my guess would be the latter). Accessing the drive's S.M.A.R.T. data indicates that the warning numbers were screamingly bad and probably were for some time.
So apparently the SI3114R doesn't monitor S.M.A.R.T. data, and it's error-handling capabilities fall somewhere between "shitty" and "non-existant". No big deal for me; I was only inconvenienced by having to re-install operating systems and applications.
The moral of this long-winded story is that you generally get what you pay for. This isn't the first bad experience I've had with on-board RAID controllers. If your data is important, then spend the appropriate money (think in terms of data replacement cost), do the appropriate research, and invest in a RAID setup that's right for your situation. If your protected data consists of anything more important than your Oblivion saved games, your mobo's RAID controller (or the $39 Fry's special) is probably the wrong choice.
And if anyone cares to know, I'm now using the NVRAID on the mobo (we'll eventually see if it handles failures more gracefully), and I use an Areca ARC-1110 on my server. I can attest that the Areca card does handle failures extremely well, albeit noisily.
Help save the critically endangered Blue Iguana
I finally broke down and bought an Areca card for one of my home-office servers (I had read some nice reviews and wanted to test one myself before recommending it). Seems reliable (at least from my single, lonely sample point) - it handled a drive failure perfectly (that is, it caught ugly S.M.A.R.T. statistics and notified us before the drive actually failed completely) - and it's very fast. Their Linux driver is BLOB-Free, well-commented and 100% GPL. Prices are reasonable, but it'd be nice if they were available through mainstream distribution (Ingram, TechData, etc) - not yet, apparently.
Help save the critically endangered Blue Iguana
...and a proprietary striping format, so when you have controller problems you have to use the same vendor's software & hardware to recover your data.
Malike Bamiyi wanted my assistance.