Does anyone know of any software RAID solutions that come close to the performance of a commodity RAID card such as LSI/3ware/Areca for direct-attached drives?
yes, MD, the standard Linux software raid, is generally faster than HW raid. yes, this can be argued, though not in any kind of slam-dunk. as far as I know, the very fastest HW raid (3ware and areca - I wouldn't guess LSI) top out at 6-800 MB/s. obviously, MD will consume some cycles supporting that kind of bandwidth, but it can be done.
for a typical cost-sensitive fileserver, especially if only over a gigabit or two, MD is a no-brainer. It Just Works and most any MB will already have ~6 sata ports, so you just plug in some disturbingly cheap 320-1000G sata disks (~60 MB/s each), and you're flying.
With the availability multi-core chips and SSE instruction sets, it would seem to me that this is doable.
SW raid has generally been the right choice for 5+ years - since the host got fast memory interfaces, basically. even the earliest MMX helped out with this stuff. and the host CPU is always going to be many times faster than the little
embedded core on a HW raid card.
Would be nice to not have to pay for those RAID cards if I don't have to. Just wondering if anything already exists.
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