基于mdadm创建与管理软raid

环境

VMware workstation 17pro

CentOS Linux release 7.9.2009 (Core)

------内存8G，16core

------硬盘系统盘100G

------四块20G硬盘

注意事项

1、在没有操作系统的情况下，可以在装系统时将磁盘做软raid，然后使用软raid作为系统盘

2、在重构时，软raid会大大增加CPU的负担，在实际生产环境中不建议使用

3、同一块盘的不同分区也可以进行软raid

4、环境硬盘均为SCSI类型，且为精简置备

创建raid0,raid1

当前环境状态

#查看当前磁盘状态
lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0  100G  0 disk 
├─sda1            8:1    0    1G  0 part /boot
└─sda2            8:2    0   99G  0 part 
  ├─centos-root 253:0    0   50G  0 lvm  /
  ├─centos-swap 253:1    0  3.9G  0 lvm  [SWAP]
  └─centos-home 253:2    0 45.1G  0 lvm  /home
sdb               8:16   0   20G  0 disk 
sdc               8:32   0   20G  0 disk 
sdd               8:48   0   20G  0 disk 
sde               8:64   0   20G  0 disk 
sr0              11:0    1  4.5G  0 rom  /run/media/root/CentOS 7 x86_64

安装mdadm

#如果是经过yum update那么大概率是不用安装的

yum -y install mdadm

创建raid

#创建raid
#创建raid名为/dev/md0，选另外名字可能报错 使用mdadm -C亦可
mdadm --create /dev/md0 \
-a yes \ #自动创建raid设备
-l 0 \ #设定raid类型为raid0
-n 2 /dev/sdb /dev/sdc #指定2块硬盘，sdb与sdc

#成功会显示
#mdadm: Defaulting to version 1.2 metadata
#mdadm: array /dev/md1 started.

mdadm --create /dev/md1 -a yes -l 1 -n 2 /dev/sdd /dev/sde
#输入yes忽略提示

查看软raid信息

#查看软raid信息
lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda               8:0    0  100G  0 disk  
├─sda1            8:1    0    1G  0 part  /boot
└─sda2            8:2    0   99G  0 part  
  ├─centos-root 253:0    0   50G  0 lvm   /
  ├─centos-swap 253:1    0  3.9G  0 lvm   [SWAP]
  └─centos-home 253:2    0 45.1G  0 lvm   /home
sdb               8:16   0   20G  0 disk  
└─md0             9:0    0   40G  0 raid0 
sdc               8:32   0   20G  0 disk  
└─md0             9:0    0   40G  0 raid0 
sdd               8:48   0   20G  0 disk  
└─md1             9:1    0   20G  0 raid1 
sde               8:64   0   20G  0 disk  
└─md1             9:1    0   20G  0 raid1 
sr0              11:0    1  4.5G  0 rom   /run/media/root/CentOS 7 x86_64

mdadm --detail /dev/md0
#mdadm -D /dev/md0
/dev/md0:
           Version : 1.2
     Creation Time : Tue Dec 12 05:41:07 2023
        Raid Level : raid0
        Array Size : 41908224 (39.97 GiB 42.91 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Tue Dec 12 05:41:07 2023 
             State : clean
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

        Chunk Size : 512K

Consistency Policy : none

              Name : 192.168.8.151:0  (local to host 192.168.8.151)
              UUID : cb7e5ace:f809e250:75079d40:21413521
            Events : 0

    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync   /dev/sdb
       1       8       32        1      active sync   /dev/sdc
#查看raid状态
cat /proc/mdstat 
Personalities : [raid0] [raid1] 
md1 : active raid1 sde[1] sdd[0]
      20954112 blocks super 1.2 [2/2] [UU]
      
md0 : active raid0 sdc[1] sdb[0]
      41908224 blocks super 1.2 512k chunks

停止与启动阵列，添加删除硬盘

#停止阵列
mdadm --stop /dev/md0
mdadm --stop /dev/md1

#重新启动阵列
mdadm -A /dev/md1

#清除使用后的raid超级块信息
mdadm --misc --zero-superblock /dev/sdb /dev/sdc
#将信息彻底清除，使其可以再被用于创建新阵列

#模拟磁盘故障
mdadm /dev/md1 -f /dev/sdd 

#查看信息
cat /proc/mdstat 
Personalities : [raid0] [raid1] 
md1 : active raid1 sde[1] sdd[0](F)
      20954112 blocks super 1.2 [2/1] [_U]
mdadm -D /dev/md1 
/dev/md1:
           Version : 1.2
     Creation Time : Tue Dec 12 06:43:12 2023
        Raid Level : raid1
        Array Size : 20954112 (19.98 GiB 21.46 GB)
     Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Tue Dec 12 06:47:50 2023
             State : clean, degraded 
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 1
     Spare Devices : 0


#移除故障的磁盘
mdadm --manage /dev/md1 --remove /dev/sdd

#此时再查看就只剩一块盘了
mdadm -D /dev/md1
/dev/md1:
           Version : 1.2
     Creation Time : Tue Dec 12 06:43:12 2023
        Raid Level : raid1
        Array Size : 20954112 (19.98 GiB 21.46 GB)
     Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 1
       Persistence : Superblock is persistent

       Update Time : Tue Dec 12 06:50:27 2023
             State : clean, degraded 
    Active Devices : 1
   Working Devices : 1
    Failed Devices : 0
     Spare Devices : 0

#再添加一块好的盘进去
mdadm --manage /dev/md1 --add /dev/sdc

#此时再查看mdstat状态，可以看到硬盘正在重构
cat /proc/mdstat 
Personalities : [raid0] [raid1] 
md1 : active raid1 sdc[2] sde[1]
      20954112 blocks super 1.2 [2/1] [_U]
      [=>...................]  recovery =  8.5% (1800192/20954112) finish=1.4min speed=225024K/sec

#重构完重新查看
mdadm -D /dev/md1 
/dev/md1:
           Version : 1.2
     Creation Time : Tue Dec 12 06:43:12 2023
        Raid Level : raid1
        Array Size : 20954112 (19.98 GiB 21.46 GB)
     Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Tue Dec 12 06:56:35 2023
             State : clean 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

Consistency Policy : resync

#清理环境
mdadm --stop /dev/md1
mdadm --misc --zero-superblock /dev/sdc /dev/sde

创建raid5

#创建raid5
mdadm --create /dev/md0 -a yes -l 5 -n 2 -x 2 /dev/sdb /dev/sdc /dev/sdd /dev/sde
#-x 是指定热备盘数量

#查看信息，可以看到正在重构
cat /proc/mdstat  
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] 
md0 : active raid5 sdc[4] sde[3](S) sdd[2](S) sdb[0]
      20954112 blocks super 1.2 level 5, 512k chunk, algorithm 2 [2/1] [U_]
      [==>..................]  recovery = 14.3% (3000192/20954112) finish=1.4min speed=200012K/sec

mdadm -D /dev/md0 
/dev/md0:
           Version : 1.2
     Creation Time : Tue Dec 12 07:05:36 2023
        Raid Level : raid5
        Array Size : 20954112 (19.98 GiB 21.46 GB)
     Used Dev Size : 20954112 (19.98 GiB 21.46 GB)
      Raid Devices : 2
     Total Devices : 4
       Persistence : Superblock is persistent

       Update Time : Tue Dec 12 07:06:48 2023
             State : clean, degraded, recovering 
    Active Devices : 1
   Working Devices : 4
    Failed Devices : 0
     Spare Devices : 3

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : resync

    Rebuild Status : 69% complete

              Name : 192.168.8.151:0  (local to host 192.168.8.151)
              UUID : 82e7f291:65e54bf3:d96624ce:964e3637
            Events : 12

    Number   Major   Minor   RaidDevice State
       0       8       16        0      active sync   /dev/sdb
       4       8       32        1      spare rebuilding   /dev/sdc

       2       8       48        -      spare   /dev/sdd
       3       8       64        -      spare   /dev/sde

lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda               8:0    0  100G  0 disk  
├─sda1            8:1    0    1G  0 part  /boot
└─sda2            8:2    0   99G  0 part  
  ├─centos-root 253:0    0   50G  0 lvm   /
  ├─centos-swap 253:1    0  3.9G  0 lvm   [SWAP]
  └─centos-home 253:2    0 45.1G  0 lvm   /home
sdb               8:16   0   20G  0 disk  
└─md0             9:0    0   20G  0 raid5 
sdc               8:32   0   20G  0 disk  
└─md0             9:0    0   20G  0 raid5 
sdd               8:48   0   20G  0 disk  
└─md0             9:0    0   20G  0 raid5 
sde               8:64   0   20G  0 disk  
└─md0             9:0    0   20G  0 raid5 


#查看系统集成的mod，能看到kernal有支持raid的mod
lsmod | grep raid
raid456               151196  1 
async_raid6_recov      17288  1 raid456
async_memcpy           12768  2 raid456,async_raid6_recov
async_pq               13332  2 raid456,async_raid6_recov
raid6_pq              102527  3 async_pq,raid456,async_raid6_recov
async_xor              13127  3 async_pq,raid456,async_raid6_recov
async_tx               13509  5 async_pq,raid456,async_xor,async_memcpy,async_raid6_recov
raid1                  44113  0 
raid0                  18164  0 
libcrc32c              12644  4 xfs,raid456,nf_nat,nf_conntrack