Am Sun, 15 May 2016 19:24:47 +0900 schrieb Tomasz Chmielewski <man...@wpkg.org>:
> I'm trying to read two large files in parallel from a 2-disk RAID-1 > btrfs setup (using kernel 4.5.3). > > According to iostat, one of the disks is 100% saturated, while the > other disk is around 0% busy. > > Is it expected? > > With two readers from the same disk, each file is being read with ~50 > MB/s from disk (with just one reader from disk, the speed goes up to > around ~150 MB/s). > > > In md RAID, with many readers, it will try to distribute the reads - > after md manual on http://linux.die.net/man/4/md: > > Raid1 > (...) > Data is read from any one device. The driver attempts to > distribute read requests across all devices > to maximise performance. > > Raid5 > (...) > This also allows more parallelism when reading, as read requests > are distributed over all the devices > in the array instead of all but one. > > > Are there any plans to improve this is btrfs? > > > Tomasz Chmielewski > http://wpkg.org Here is an idea that could need improvement: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/17985 -- Regards, Kai Replies to list-only preferred. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
