'md' performs wonderfully. Thanks to every contributor! I pitted it against a 3ware 9650 and 'md' won on nearly every account (albeit on RAID5 for sequential I/O the 3ware is a distant winner): http://www.makarevitch.org/rant/raid/#3wmd
On RAID10 f2 a small read-ahead reduces the throughput on sequential read, but even a low value (768 for the whole 'md' block device, 0 for the underlying spindles) enables very good sequential read performance (300 MB/s on 6 low-end Hitachi 500 GB spindles). What baffles me is that, on a 1.4TB array served by a box having 12 GB RAM (low cache-hit ratio), the random access performance remains stable and high (450 IOPS with 48 threads, 20% writes - 10% fsync'ed), even with a fairly high read-ahead (16k). How comes?! - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
