linux做软RAID10
最近拿到的几个12块盘的服务器，都是没有RAID卡的。自己就简单做了一下软RAID。
- 用/dec/sd[b-l]1创建一个raid10的/dev/md1，其中一个做备用盘。
mdadm --create /dev/md1 --run --level=10 -n 10 /dev/sd[b-l] -x 1
mkdir /mnt/data ; mkfs.ext4 /dev/md1
2.把mda1加到fstab
/dev/md1 /mnt/data ext4 defaults,noatime 0 0
3.把阵列信息加到/etc/mdadm.conf
mdadm –detail –scan » /etc/mdadm.conf
状态查看可以
#cat /proc/mdstat
Personalities : [raid10]
md1 : active raid10 sdl[10](S) sdk[9] sdj[8] sdi[7] sdh[6] sdg[5] sdf[4] sde[3] sdd[2] sdc[1] sdb[0]
9767564800 blocks super 1.2 512K chunks 2 near-copies [10/10] [UUUUUUUUUU]
unused devices: <none>
#mdadm --detail /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Sat Jul 20 00:33:49 2013
Raid Level : raid10
Array Size : 9767564800 (9315.08 GiB 10001.99 GB)
Used Dev Size : 1953512960 (1863.02 GiB 2000.40 GB)
Raid Devices : 10
Total Devices : 11
Persistence : Superblock is persistent
Update Time : Sat Jul 20 08:33:55 2013
State : active
Active Devices : 10
Working Devices : 11
Failed Devices : 0
Spare Devices : 1
Layout : near=2
Chunk Size : 512K
Name : xxx
UUID : xxx
Events : 18
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
4 8 80 4 active sync /dev/sdf
5 8 96 5 active sync /dev/sdg
6 8 112 6 active sync /dev/sdh
7 8 128 7 active sync /dev/sdi
8 8 144 8 active sync /dev/sdj
9 8 160 9 active sync /dev/sdk
10 8 176 - spare /dev/sdl
单个盘的操作
1.卸掉故障盘
mdadm /dev/md1 -f /dev/sdd
mdadm /dev/md1 -r /dev/sdd
2.恢复单个盘
mdadm –zero-superblock /dev/sdd
mdadm /dev/md1 -a /dev/sdd
3.停掉整个RAID
mdadm –stop /dev/md1
4.启动整个RAID
mdadm -A /dev/md1
简单测试了一下RAID的性能和单个盘的性能差别
RAID10：
#dd if=/dev/zero of=test1 bs=1024000 count=10240 oflag=direct ;sleep 5; dd if=test1 of=/dev/null bs=1024000 count=10240 iflag=direct
10240+0 records in
10240+0 records out
10485760000 bytes (10 GB) copied, 20.4646 s, 512 MB/s
10240+0 records in
10240+0 records out
10485760000 bytes (10 GB) copied, 15.0176 s, 698 MB/s
单个盘：
#dd if=/dev/zero of=test1 bs=1024000 count=10240 oflag=direct ;sleep 5; dd if=test1 of=/dev/null bs=1024000 count=10240 iflag=direct
10240+0 records in
10240+0 records out
10485760000 bytes (10 GB) copied, 62.761 s, 167 MB/s
10240+0 records in
10240+0 records out
10485760000 bytes (10 GB) copied, 61.865 s, 169 MB/s
做了RAID后读取的是基本是把SAS卡的6G的带宽跑满了，写入也有三倍左右的提升。