在 CentOS 6.9X64 上使用 RAID 5 – 多 1 個站長 ( One More WebMaster )

在 CentOS 6.9X64 上使用 RAID 5

星期五, 23六月2017
1. 安裝 mdadm 套件 
# yum install mdadm 
2. 查看目前磁碟狀態 
# fdisk -l | grep ‘Disk /dev/sd’ 
Disk /dev/sda: 10.7 GB, 10737418240 bytes 
Disk /dev/sdb: 21.5 GB, 21474836480 bytes 
Disk /dev/sdc: 21.5 GB, 21474836480 bytes 
Disk /dev/sdd: 21.5 GB, 21474836480 bytes 
Disk /dev/sde: 21.5 GB, 21474836480 bytes

3. 建立磁碟分割區 
# fdisk /dev/sdb 

重複上面的動作，完成所有的磁碟 
# fdisk /dev/sdc 
# fdisk /dev/sdd 
# fdisk /dev/sde 

4. 建立 /dev/md0 磁碟陣列分割區
# mdadm –create –verbose –auto=yes /dev/md0 –level=5 –raid-devices=4 /dev/sd[b-e]
mdadm: layout defaults to left-symmetric
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 512K
mdadm: /dev/sdb appears to be part of a raid array:
       level=raid0 devices=0 ctime=Thu Jan  1 08:00:00 1970

mdadm: partition table exists on /dev/sdb but will be lost or
       meaningless after creating array
mdadm: /dev/sdc appears to be part of a raid array:
       level=raid0 devices=0 ctime=Thu Jan  1 08:00:00 1970
mdadm: partition table exists on /dev/sdc but will be lost or
       meaningless after creating array
mdadm: /dev/sdd appears to be part of a raid array:
       level=raid0 devices=0 ctime=Thu Jan  1 08:00:00 1970
mdadm: partition table exists on /dev/sdd but will be lost or
       meaningless after creating array
mdadm: /dev/sde appears to be part of a raid array:
       level=raid0 devices=0 ctime=Thu Jan  1 08:00:00 1970
mdadm: partition table exists on /dev/sde but will be lost or
       meaningless after creating array
mdadm: size set to 20955136K
Continue creating array? yes
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.

5. 查看建置結果
# fdisk -l | grep /dev/md0

Disk /dev/md0: 64.4 GB, 64374177792 bytes

# cat /proc/mdstat
Personalities :

[raid6]

[raid5] [raid4]
md0 : active raid5 sde[4] sdd[2] sdc[1] sdb[0]
      62865408 blocks super 1.2 level 5, 512k chunk, algorithm 2 [4/3] [UUU_]
      [>………………..]  recovery =  2.8% (607044/20955136) finish=6.7min speed=50587K/sec

unused devices:

# mdadm -D /dev/md0
/dev/md0:
        Version : 1.2
  Creation Time : Wed Jun 29 08:16:51 2016
     Raid Level : raid5
     Array Size : 62865408 (59.95 GiB 64.37 GB)
  Used Dev Size : 20955136 (19.98 GiB 21.46 GB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Wed Jun 29 08:17:14 2016
          State : clean, degraded, recovering
 Active Devices : 3
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 512K

 Rebuild Status : 6% complete

           Name : localhost.localdomain:0  (local to host localhost.localdomain)
           UUID : 17b9df4d:e3542df5:34c1a172:298a07a5
         Events : 2

    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
       4       8       64        3      spare rebuilding   /dev/sde

6. 格式化分割區
# mkfs -t ext4 /dev/md0
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=128 blocks, Stripe width=384 blocks
3932160 inodes, 15716352 blocks
785817 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
480 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group

Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624, 11239424
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 35 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

7. 建立掛載目錄並掛載 
# mkdir /home/RAID5
# mount /dev/md0 /home/RAID5
# df -h
Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/VolGroup-lv_root
                      8.3G 1022M  6.9G  13% /
tmpfs                 931M     0  931M   0% /dev/shm
/dev/sda1             477M   63M  389M  14% /boot
/dev/md0               59G   52M   56G   1% /home/RAID5
8. 查看硬碟的 UUID 
# blkid | grep /dev/md0
/dev/md0: UUID=”a24bbe2b-c0f1-4417-99d9-866ea1f2a33d” TYPE=”ext4″
9. 用 vim 或 gedit修改 /etc/fstab 
# vim(gedit) /etc/fstab 
加入下面一行

UUID=a24bbe2b-c0f1-4417-99d9-866ea1f2a33d  /home/RAID5         ext4    defaults        1 1
10. 編輯 /etc/mdadm.conf  設定檔 (後要用 vim 或 gedit 打開查看)
# mdadm –detail –scan –verbose >> /etc/mdadm.conf
ARRAY /dev/md0 level=raid5 num-devices=4 metadata=1.2 name=localhost.localdomain:0 UUID=232bc54c:6583d975:ab90c836:78be7854
   devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde
11. 重新啟動電腦
# sync;sync;reboot

12. 磁碟分割資訊
# fdisk -l | grep /dev/sd
Disk /dev/sda: 10.7 GB, 10737418240 bytes
/dev/sda1   *           1          64      512000   83  Linux
/dev/sda2              64        1306     9972736   8e  Linux LVM
Disk /dev/sdb: 21.5 GB, 21474836480 bytes
/dev/sdb1               1        2610    20964793+  fd  Linux raid autodetect
Disk /dev/sdc: 21.5 GB, 21474836480 bytes
/dev/sdc1               1        2610    20964793+  fd  Linux raid autodetect
Disk /dev/sdd: 21.5 GB, 21474836480 bytes
/dev/sdd1               1        2610    20964793+  fd  Linux raid autodetect
Disk /dev/sde: 21.5 GB, 21474836480 bytes
/dev/sde1               1        2610    20964793+  fd  Linux raid autodetect

13. 檢查是否有正確掛載
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root
                      8.3G 1022M  6.9G  13% /
tmpfs                 931M     0  931M   0% /dev/shm
/dev/sda1             477M   63M  389M  14% /boot
/dev/md0               59G   52M   56G   1% /home/RAID5