Re: mdadm, partitioned array

[michael@estone.ca]

Quoting "Douglas A. Tutty" <dtutty@porchlight.ca>:

> Well, its raid5 which is slow to begin with.  Have you verified with
> mdadm that the array is complete and not running in degraded mode (which
> would slow it down further)?

Sorry, forgot to mention that I have check mdstat to make sure the  
array is not degraded.
Here are some numbers:  (only md_d0p1 is slow, md_d0p2 and all others  
are fine)

host:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/md1              9.4G  631M  8.7G   7% /
tmpfs                 994M     0  994M   0% /lib/init/rw
udev                   10M   80K   10M   1% /dev
tmpfs                 994M     0  994M   0% /dev/shm
/dev/md0               92M   24M   64M  27% /boot
/dev/md_d0p1          6.6G  3.1G  3.6G  47% /mnt
/dev/md_d0p2          7.5G  3.1G  4.5G  41% /mnt2

host:~# cat /proc/mdstat
Personalities : [raid1] [raid10] [raid6] [raid5] [raid4]
md_d0 : active raid5 sdd3[3] sdc3[2] sdb3[1] sda3[0]
      14650944 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md1 : active raid10 sda2[0] sdd2[3] sdc2[2] sdb2[1]
      9767296 blocks 64K chunks 2 near-copies [4/4] [UUUU]

md0 : active raid1 sda1[0] sdd1[3] sdc1[2] sdb1[1]
      96256 blocks [4/4] [UUUU]

unused devices: <none>


host:/mnt# dd if=/dev/zero of=somefile.img count=6M
6291456+0 records in
6291456+0 records out
3221225472 bytes (3.2 GB) copied, 82.3717 seconds, 39.1 MB/s

host:/mnt2# dd if=/dev/zero of=somefile.img count=6M
6291456+0 records in
6291456+0 records out
3221225472 bytes (3.2 GB) copied, 32.0343 seconds, 101 MB/s

I get the same results over and over, and same with bonnie++.
The partitioned array mounted to mnt2 is normal, but mnt is really slow.

I don't get it.  :)

Thanks,
Mike