Linux AS 5软raid的实现过程

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为新添加的硬盘分区和格式化 [root@llk726 dev]# fdisk /dev/sdb Command (m for help): n（添加分区） Command action e extended p primary partition (1-4) p（创建一个主分区） Partition number (1-4): 1 First cylinder (1-130, default 1): 1 Last cylinder or +size or +sizeM or +sizeK (1-130, default 130): Using default value 130 Command (m for help): p（查看分区信息） Disk /dev/sdb: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 130 1044193+ 83 Linux Command (m for help): t （更改ID号） Selected partition 1 Hex code (type L to list codes): fd（将分区类型指定为“fd”） Changed system type of partition 1 to fd (Linux raid autodetect) Command (m for help): p Disk /dev/sdb: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 130 1044193+ fd Linux raid autodetect Command (m for help): w（保存推出） The partition table has been altered! Calling ioctl() to re-read partition table. Syncing disks. [root@localhost ~]# mkfs -t ext3 /dev/sdb1 mke2fs 1.35 (28-Feb-2004) max_blocks 267313152, rsv_groups = 8158, rsv_gdb = 63 Filesystem label= OS type: Linux Block size=4096 (log=2) Fragment size=4096 (log=2) 130560 inodes, 261048 blocks 13052 blocks (5.00%) reserved for the super user First data block=0 Maximum filesystem blocks=268435456 8 block groups 32768 blocks per group, 32768 fragments per group 16320 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376 Writing inode tables: done inode.i_blocks = 2528, i_size = 4243456 Creating journal (4096 blocks): done Writing superblocks and filesystem accounting information: done This filesystem will be automatically checked every 30 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override. 其余硬盘进行相同处理

查看硬盘分区情况 [root@llk726 dev]# fdisk -l Disk /dev/sda: 8589 MB, 8589934592 bytes 255 heads, 63 sectors/track, 1044 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sda1 * 1 13 104391 83 Linux /dev/sda2 14 395 3068415 83 Linux /dev/sda3 396 446 409657+ 82 Linux swap / Solaris /dev/sda4 447 1044 4803435 5 Extended /dev/sda5 447 1044 4803403+ 83 Linux Disk /dev/sdb: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 1 130 1044193+ fd Linux raid autodetect Disk /dev/sdc: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdc1 1 130 1044193+ fd Linux raid autodetect Disk /dev/sdd: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdd1 1 130 1044193+ fd Linux raid autodetect Disk /dev/sde: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sde1 1 130 1044193+ fd Linux raid autodetect Disk /dev/sdf: 1073 MB, 1073741824 bytes 255 heads, 63 sectors/track, 130 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdf1 1 130 1044193+ fd Linux raid autodetect

创建RAID 5 [root@llk726 dev]# mdadm -Cv /dev/md0 -l5 -n4 -x1 -c128 /dev/sd[b,c,d,e,f]1 mdadm: layout defaults to left-symmetric mdadm: /dev/sdb1 appears to contain an ext2fs file system size=1044192K mtime=Thu Jan 1 08:00:00 1970 mdadm: /dev/sdc1 appears to contain an ext2fs file system size=1044192K mtime=Thu Jan 1 08:00:00 1970 mdadm: /dev/sdd1 appears to contain an ext2fs file system size=1044192K mtime=Thu Jan 1 08:00:00 1970 mdadm: /dev/sde1 appears to contain an ext2fs file system size=1044192K mtime=Thu Jan 1 08:00:00 1970 mdadm: /dev/sdf1 appears to contain an ext2fs file system size=1044192K mtime=Thu Jan 1 08:00:00 1970 mdadm: size set to 1044096K Continue creating array? Continue creating array? (y/n) y mdadm: array /dev/md0 started. -C”指创建一个新的阵列；“/dev/md0”表示阵列设备名称；“-l5”表示设置阵列模式，可以选择0、1、4、 5、6，它们分别对应于RAID0、RAID1、RAID4、RAID5、RAID6，这里设为RAID5模式；“-n3”指设置阵列中活动设备的数目，该数目加上备用设备的数目应等于阵列中的总设备数; “-x1”设置阵列中备份设备的数目，当前阵列中含有1个备份设备；“-c128”指设置块的尺寸为128KB，缺省为64KB；“/dev/sd[b, c,d,e,f]1”指当前阵列中包含的所有设备标识符，也可以分开来写，中间用空格分开，其中最后一个为备份设备。

以上做完如果重启机器，他的raid 不能保存，需要手工维护/etc/mdadm.conf文件 [root@llk726 etc]# echo DEVICE /dev/hdb1 /dev/hdc1 /dev/hdd1 /dev/hde1 /dev/hdf1> /etc/mdadm.conf [root@llk726 etc]# mdadm –detail -scan >> /etc/mdadm.conf

创建文件系统并挂接 RAID5已经启动并处于运行状态，现在要做的就是在其上创建一个文件系统，这里使用mkfs命令，文件系统类型为ext3。命令如下： # mkfs -t ext3 /dev/md0 当新的文件系统生成之后，就可以将/dev/md0挂接到指定的目录了。命令如下： # mount -t ext3 /dev/md0 /home/raid5 为了让系统在启动时自动将/dev/md0挂接到/home/raid5，还需要修改/etc/fstab文件，添加如下内容： /dev/md0 /home/raid5 ext3 defaults 0 0

raid5的恢复 将/dev/sdb1标记为已损坏的设备 [root@llk726 etc]# mdadm -f /dev/md0 /dev/sdb1 mdadm: set /dev/sdb1 faulty in /dev/md0 [root@llk726 etc]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdf1[4] sde1[3] sdd1[2] sdc1[1] sdb1[5](F) 3132288 blocks level 5, 128k chunk, algorithm 2 [4/3] [_UUU] [===&gt;……………..] recovery = 15.6% (164056/1044096) finish=2.1min speed=6835K/sec unused devices: <none> 等一会再查看一下，刚才作为备用的磁盘己经加到raid5中，并做好了数据同步 [root@llk726 etc]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdf1[0] sde1[3] sdd1[2] sdc1[1] sdb1[4](F) 3132288 blocks level 5, 128k chunk, algorithm 2 [4/4] [UUUU] unused devices: <none>

移除坏掉的磁盘 [root@llk726 etc]# mdadm –remove /dev/md0 /dev/sdb1 mdadm: hot removed /dev/sdb1 [root@llk726 etc]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdf1[0] sde1[3] sdd1[2] sdc1[1] 3132288 blocks level 5, 128k chunk, algorithm 2 [4/4] [UUUU] unused devices: <none> 添加一块新磁盘，作为备份用（先要进行fdisk /dev/sd*分区和格式化） [root@llk726 etc]# mdadm -a /dev/md0 /dev/sdb1 mdadm: added /dev/sdb1 [root@llk726 etc]# cat /proc/mdstat Personalities : [raid6] [raid5] [raid4] md0 : active raid5 sdb1[4](S) sdf1[0] sde1[3] sdd1[2] sdc1[1] 3132288 blocks level 5, 128k chunk, algorithm 2 [4/4] [UUUU] unused devices: <none> 这时sdb1作为备份设备再次出现在阵列中