Is it possible the data-set you are testing with is too small? Modern drives have caches of around 32MB, your test might only be executing within the drive's caches. On Tue, Nov 3, 2009 at 4:37 AM, Sujit K M <sjt.kar@xxxxxxxxx> wrote: > This I think is an reported bug. > > On Mon, Nov 2, 2009 at 11:58 PM, Chris Worley <worleys@xxxxxxxxx> wrote: >> I expect RAID1 write performance to be, at best, the performance of >> the slowest drive. >> >> I'm seeing twice the performance, as if it were a RAID0. The read >> performance is 2x also, which is what I would expect. >> >> I'm using the incantation: >> >> mdadm --create /dev/md0 --chunk=256 --level=1 --assume-clean >> --raid-devices=2 /dev/sd[bc] >> >> I use "assume clean" on the fresh create, as there is no reason to >> sync the new drives. >> >> My "fio" test uses O_DIRECT with 64 threads, each with a queue depth >> of 64, running for 10 minutes. All caching is disabled, and the NOOP >> scheduler is being used. I run this test all the time, and can't >> imagine why it's getting such repeatably good write performance. >> >> Any ideas? >> >> Thanks, >> >> Chris >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > > -- > -- Sujit K M > > blog(http://kmsujit.blogspot.com/) > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
