mdadm 软件RAID 0方法

注：mdadm: SET_ARRAY_INFO failed for /dev/md0: Device or resource busy 遇到此问题，首先用fdisk -l 查看磁盘的ID 项是否为fd。然后进入/etc/fstab 把相应的磁盘类型若是ext2改为fd，重启生效. 用mount 查看，若成功是看不到相应盘。如下：要做的盘分别为sdb1、sdc1、sdd1

失败：/dev/sda2 on / type ext3 (rw)
none on /proc type proc (rw)
none on /sys type sysfs (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
usbfs on /proc/bus/usb type usbfs (rw)
/dev/sda1 on /boot type ext3 (rw)
none on /dev/shm type tmpfs (rw)
/dev/sda3 on /home type ext3 (rw)
/dev/sdb1 on /mnt/sdb1 type ext2 (rw)
/dev/sdc1 on /mnt/sdc1 type ext2 (rw)
/dev/sdd1 on /mnt/sdd1 type ext2 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
none on /proc/fs/vmblock/mountPoint type vmblock (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

 

成功：/dev/sda2 on / type ext3 (rw)
none on /proc type proc (rw)
none on /sys type sysfs (rw)
none on /dev/pts type devpts (rw,gid=5,mode=620)
usbfs on /proc/bus/usb type usbfs (rw)
/dev/sda1 on /boot type ext3 (rw)
none on /dev/shm type tmpfs (rw)
/dev/sda3 on /home type ext3 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
none on /proc/fs/vmblock/mountPoint type vmblock (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)

 

 

 

此处为下面步骤2磁盘划分分区的详情：

如果MD驱动被编译到内核中，当内核调用执行MD驱动时会自动查找分区为FD(Linux raid autodetect)格式的磁盘。所以一般会使用fdisk工具将HD磁盘或者SD磁盘分区，再设置为FD的磁盘。

[root@fc5 mdadm-2.6.3]# fdisk /dev/sdk
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.

Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-512, default 1):1
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-512, default 512):512
Using default value 512

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): FD
Changed system type of partition 1 to fd (Linux raid autodetect)

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@fc5 mdadm-2.6.3]# fdisk -l /dev/sdk
Disk /dev/sdk: 1073 MB, 1073741824 bytes
128 heads, 32 sectors/track, 512 cylinders
Units = cylinders of 4096 * 512 = 2097152 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdk1               1         512     1048560   fd  Linux raid autodetect
 

软RAID阵列实际上也可以使用任何标准的块设备作为底层设备，如SCSI设备、IDE设备、RAM disk磁盘和NBD(Network Block Device)等，甚至是其他的MD设备。

 

步骤：

1.  fdisk -l

显示所有硬盘，查看它的编号。/dev/hda,/dev/hdb,等等。

然后再依次对其 fdisk /dev/hdb

2. 新建一个分区。选择全部分配，按“n“新建——”P“ 主分区——创建一个主分区成功。——“T”更改分区类型（ID），——输入“fd”——“W”写入磁盘。

3. 对其它一块要组成阵列的磁盘进行以上同样的操作。

4. 然后： mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/hdb1 /dev/hdd1

或者这样写。mdadm -C /dev/md0 -l0 -n2 /dev/hd{b,d}1

然后对它格式化 mkfs.ext3 /dev/md0，

挂接。mkdir /mnt/md0

mount /dev/md0 /mnt/md0