# mdadm --zero-superblock /dev/sda3
# mdadm --zero-superblock /dev/sdb3
# mdadm --zero-superblock /dev/sdc3
# mdadm --zero-superblock /dev/sdd3
# mdadm --create -l 1 -n 2 /dev/md1 /dev/sd[ab]3
# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [raid10]
md1 : active raid1 sdb3[1] sda3[0]
      390448192 blocks [2/2] [UU]
      [>....................]  resync =  1.0% (4048000/390448192) finish=134.1min speed=47992K/sec
md0 : active raid1 sda1[0] sdd1[3] sdc1[2] sdb1[1]
      131456 blocks [4/4] [UUUU]

unused devices: <none>
# cd /proc/sys/dev/raid/
# cat speed_limit_max > speed_limit_min
# cat speed_limit_min
200000
# cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid5] [raid10]
md1 : active raid1 sdb3[1] sda3[0]
      390448192 blocks [2/2] [UU]
      [>....................]  resync =  1.8% (7035200/390448192) finish=133.7min speed=47793K/sec
md0 : active raid1 sda1[0] sdd1[3] sdc1[2] sdb1[1]
      131456 blocks [4/4] [UUUU]

unused devices: <none>
# mkfs.xfs -f -b size=1024 /dev/md1
# mount /nas
# cd /nas
# time dd if=/dev/zero of=test bs=512k count=2048
real    1m22.509s user    0m0.020s sys     0m36.840s
# rm test
# time dd if=/dev/zero of=test bs=256k count=4096
real    1m22.649s user    0m0.080s sys     0m36.590s
# echo 5 > /proc/sys/vm/swappiness
# rm test
# time dd if=/dev/zero of=test bs=256k count=4096
real    1m22.721s user    0m0.040s sys     0m36.480s
# rm test;time dd if=/dev/zero of=test bs=128k count=8192
real    1m23.661s user    0m0.140s sys     0m37.370s
# rm test;time dd if=/dev/zero of=test bs=32k count=32768
real    1m30.770s user    0m0.460s sys     0m44.490s
# rm test;time dd if=/dev/zero of=test bs=1024k count=1024
# time dd if=/dev/zero of=/dev/sdd3 bs=1024k count=1024
real    1m12.170s user    0m0.020s sys     0m32.490s
# time dd if=/dev/zero of=/dev/sdd3 bs=32k count=32768
real    1m19.790s user    0m0.360s sys     0m40.470s
# time dd if=/dev/sdd3 of=/dev/null bs=32k count=32768
real    0m49.020s
user    0m0.090s
sys     0m41.070s
# time dd if=/dev/sdd3 of=/dev/null bs=1024k count=1024
real    0m47.271s
user    0m0.010s
sys     0m40.270s
# time dd if=/dev/md1 of=/dev/null bs=1024k count=1024
real    1m6.390s
user    0m0.030s
sys     0m58.930s
# time dd if=test of=/dev/null bs=1024k count=1024
1024+0 records in
1024+0 records out

real    0m27.380s
user    0m0.010s
sys     0m12.400s
# time dd if=test of=/dev/null bs=1024k count=1024
1024+0 records in
1024+0 records out

real    0m27.101s
user    0m0.000s
sys     0m13.200s
sh-2.05b# blktool /dev/sdd wcache on
sh-2.05b# time dd if=/dev/zero of=/dev/sdd3 bs=1024k count=1024
1024+0 records in
1024+0 records out
1073741824 bytes transferred in 66.209057 seconds (16217446 bytes/sec)

real    1m6.220s
user    0m0.030s
user    0m0.030s
sys     0m33.650s


+No network interfaces found
EM-7210 ver.T04 2005-12-12 (For ver.AA)
== Executing boot script in 1.000 seconds - enter ^C to abort
RedBoot> exec -b 0x01008000 -l 0x00200000 -c "ip=bootp" 0x01800000