On 30/12/11 07:28, Michele Codutti wrote:
Hi all, I'm writing to this mailing list because I cannot figure out why I had some performance issues with my three WD20EARS (2TB Western Digital "Green" 4K/AF drive). These drives has a (sequential) write throughput around 100MB/s. When I combine them in a RAID0 configuration the throughput is around 300 MB/s and in a RAID1 configuration they preserve a single drive performance of 100MB/s. When I combine all three drives in a RAID5 configuration the (individual) performance falls around 40MB/s. I get the same performance level when I do individual misaligned writes (ex: dd if=/dev/zero bs=6K of=/dev/sda). The drives are not partitioned. I'm using the default chunk size (512K) and the default metadata superblock version (1.2). I had not formatted the RAID or any single drive during my test i had directly used the raw devices. I'm using a 11.10 ubuntu with 3.0.0 linux kernel and 3.1.4 mdadm. The hardware is a HP microserver.
Just a thought, but do you have the "XP mode" jumper removed on all drives? Regards, Brad -- 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
