Re: Typical RAID5 transfer speeds
From: Andre Tomt <hidden>
Date: 2009-12-20 14:53:08
On 20.12.2009 10:55, Thomas Fjellstrom wrote:
While the driver support isn't "perfect"*, I have an AOC-SASLP-MV8, a 2 port SAS 4x PCI-e card. (with SAS->SATA converters, its an 8 port SATA card) When I was running some tests on individual drives, and watching iostat, I saw over 500MB/s combined throughput, and that was with only 5 drives. Theoretically it should be capable of 1GB/s given its a x4 card. Theoretically. At the very least, the card should be more than capable of providing enough bandwidth for all 8 ports to be filled with regular mechanical hard drives (sans port expanders).
Having tried it connected directly to the north bridge, it seems to top out at ~650-700MB/s (also using Windows driver). Which is not too bad for a pcie 1.0 x4 card, but unfortunatly will only manage to saturate about ~5 modern mechanical drives (currently at 120-130MB/s each for SATA 7200rpm), if high sequential performance is all you're looking for. Currently I solved that by having 4 drives from the array on that card, and populating the last four ports with with drives that are seldomly used and when used get mostly random i/o but still needs a port ;-) Still good value for money, indeed.