# 实测软Raid

## 一、环境介绍

| 操作系统             | 硬盘1   | 硬盘2   |
| -------------------- | ------- | ------- |
| ubuntu24.04 云服务器 | 70g ssd | 70g ssd |

## 二、测试创建Raid 1

1、创建Raid 1

```
root@VM-2-2-ubuntu:/data# mdadm -C /dev/md0 -l 1 -n 2 /dev/vdb /dev/vdc 
mdadm: Note: this array has metadata at the start and
    may not be suitable as a boot device.  If you plan to
    store '/boot' on this device please ensure that
    your boot-loader understands md/v1.x metadata, or use
    --metadata=0.90
Continue creating array? y
mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md0 started.
```

2、查看创建进度

```
###查看raid进度###
root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdc[1] vdb[0]
      73333760 blocks super 1.2 [2/2] [UU]
      [===>.................]  resync = 15.5% (11405312/73333760) finish=5.0min speed=206165K/sec
      
unused devices: <none>
```

3、创建完成

```
###Raid进度完成###
root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdc[1] vdb[0]
      73333760 blocks super 1.2 [2/2] [UU]
      
unused devices: <none>
```

4、格式化磁盘

```
###格式化###
root@VM-2-2-ubuntu:/data# mkfs.xfs /dev/md0 
meta-data=/dev/md0               isize=512    agcount=4, agsize=4583360 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=1, sparse=1, rmapbt=1
         =                       reflink=1    bigtime=1 inobtcount=1 nrext64=0
data     =                       bsize=4096   blocks=18333440, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0, ftype=1
log      =internal log           bsize=4096   blocks=16384, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
```

5、挂载

```
root@VM-2-2-ubuntu:/data# mount /dev/md0 /data

root@VM-2-2-ubuntu:/data# df -h 
Filesystem      Size  Used Avail Use% Mounted on
tmpfs           197M  1.1M  196M   1% /run
/dev/vda2        50G  4.9G   43G  11% /
tmpfs           984M   24K  984M   1% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           197M   12K  197M   1% /run/user/1000
/dev/md0         70G  1.4G   69G   2% /data

root@VM-2-2-ubuntu:~# ls -l /dev/disk/by-id
total 0
lrwxrwxrwx 1 root root 9 May  8 16:10 ata-QEMU_DVD-ROM_QM00002 -> ../../sr0
lrwxrwxrwx 1 root root 9 May  8 16:44 md-name-VM-2-2-ubuntu:0 -> ../../md0
lrwxrwxrwx 1 root root 9 May  8 16:44 md-uuid-261fcd66:9689a33e:294c4f85:6e096e48 -> ../../md0
lrwxrwxrwx 1 root root 9 May  8 16:10 virtio-disk-f6vtxkjm -> ../../vdb
lrwxrwxrwx 1 root root 9 May  8 16:10 virtio-disk-ld0km1yk -> ../../vdc
```

6、写入数据测试性能，并计算文件的md5值

```
root@VM-2-2-ubuntu:/data# dd if=/dev/zero of=sun.txt bs=1M count=2048
2048+0 records in
2048+0 records out
2147483648 bytes (2.1 GB, 2.0 GiB) copied, 4.83928 s, 444 MB/s

root@VM-2-2-ubuntu:/data# md5sum sun.txt 
a981130cf2b7e09f4686dc273cf7187e  sun.txt
```

三、模拟单盘故障，拔掉异常的盘，然后添加新盘

1、卸载vdb，尝试读取写入文件

```
root@VM-2-2-ubuntu:~# ls -l /dev/disk/by-id
total 0
lrwxrwxrwx 1 root root 9 May  8 16:10 ata-QEMU_DVD-ROM_QM00002 -> ../../sr0
lrwxrwxrwx 1 root root 9 May  8 16:44 md-name-VM-2-2-ubuntu:0 -> ../../md0
lrwxrwxrwx 1 root root 9 May  8 16:44 md-uuid-261fcd66:9689a33e:294c4f85:6e096e48 -> ../../md0
lrwxrwxrwx 1 root root 9 May  8 16:10 virtio-disk-ld0km1yk -> ../../vdc

###可正常读取###
root@VM-2-2-ubuntu:/data# md5sum sun.txt 
a981130cf2b7e09f4686dc273cf7187e  sun.txt

root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdc[1]
      73333760 blocks super 1.2 [2/1] [_U]
      
unused devices: <none>


root@VM-2-2-ubuntu:/data# rz -E
Sent - Linux内核设计与实现（第三版）.pdf  9.72 MB/s Spend: 4 seconds
root@VM-2-2-ubuntu:/data# ls
Linux内核设计与实现（第三版）.pdf  sun.txt  通用交流材料_95_1744028634000.pptx
```

2、加回单盘，这里有点难受的是需要进行全盘数据校验

1. **全盘数据校验机制**
   RAID1 的同步并非仅针对已写入文件，而是对整块硬盘的 ​**所有存储单元（包括空白区域）​**​ 进行校验

   即使你只拔插硬盘，RAID 控制器仍需逐块比对数据一致性，确保两个硬盘的镜像完全一致。

2. **触发同步的条件**
   当硬盘被移除后重新插入时，RAID 控制器会将其标记为「潜在不一致状态」，即使文件系统未损坏，仍需通过全盘同步消除数据差异风险

```
root@VM-2-2-ubuntu:/data# ls -al /dev/disk/by-id
total 0
drwxr-xr-x 2 root root 140 May  9 10:51 .
drwxr-xr-x 8 root root 160 May  8 16:10 ..
lrwxrwxrwx 1 root root   9 May  8 16:10 ata-QEMU_DVD-ROM_QM00002 -> ../../sr0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-name-VM-2-2-ubuntu:0 -> ../../md0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-uuid-261fcd66:9689a33e:294c4f85:6e096e48 -> ../../md0
lrwxrwxrwx 1 root root   9 May  9 10:51 virtio-disk-f6vtxkjm -> ../../vdb
lrwxrwxrwx 1 root root   9 May  8 16:10 virtio-disk-ld0km1yk -> ../../vdc


root@VM-2-2-ubuntu:/data# mdadm --add /dev/md0 /dev/vdb

root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdb[2] vdc[1]
      73333760 blocks super 1.2 [2/2] [UU]
      
unused devices: <none>
```

3、干掉另外一块盘，测试数据完整性并同样加回

```
root@VM-2-2-ubuntu:/data# ls -al /dev/disk/by-id
total 0
drwxr-xr-x 2 root root 120 May  9 11:11 .
drwxr-xr-x 8 root root 160 May  8 16:10 ..
lrwxrwxrwx 1 root root   9 May  8 16:10 ata-QEMU_DVD-ROM_QM00002 -> ../../sr0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-name-VM-2-2-ubuntu:0 -> ../../md0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-uuid-261fcd66:9689a33e:294c4f85:6e096e48 -> ../../md0
lrwxrwxrwx 1 root root   9 May  9 10:51 virtio-disk-f6vtxkjm -> ../../vdb

root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdb[2]
      73333760 blocks super 1.2 [2/1] [U_]
      
unused devices: <none>

root@VM-2-2-ubuntu:/data# md5sum sun.txt 
a981130cf2b7e09f4686dc273cf7187e  sun.txt

root@VM-2-2-ubuntu:/data# ls -al /dev/disk/by-id
total 0
drwxr-xr-x 2 root root 140 May  9 11:13 .
drwxr-xr-x 8 root root 160 May  8 16:10 ..
lrwxrwxrwx 1 root root   9 May  8 16:10 ata-QEMU_DVD-ROM_QM00002 -> ../../sr0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-name-VM-2-2-ubuntu:0 -> ../../md0
lrwxrwxrwx 1 root root   9 May  8 16:44 md-uuid-261fcd66:9689a33e:294c4f85:6e096e48 -> ../../md0
lrwxrwxrwx 1 root root   9 May  9 10:51 virtio-disk-f6vtxkjm -> ../../vdb
lrwxrwxrwx 1 root root   9 May  9 11:13 virtio-disk-ld0km1yk -> ../../vdc

root@VM-2-2-ubuntu:/data# mdadm --add /dev/md0 /dev/vdc
mdadm: added /dev/vdc
root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdc[3] vdb[2]
      73333760 blocks super 1.2 [2/1] [U_]
      [>....................]  recovery =  0.8% (601728/73333760) finish=6.0min speed=200576K/sec
      
unused devices: <none>
```

四、模拟raid 1 扩容（拔盘之前优先关机，再拔盘，然后开机！！！）

1、扩容单硬盘至75G，然后挂载加回

```
root@VM-2-2-ubuntu:/data# mdadm --add /dev/md0 /dev/vdc
mdadm: added /dev/vdc

root@VM-2-2-ubuntu:/data# cat /proc/mdstat 
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md0 : active raid1 vdc[3] vdb[2]
      73333760 blocks super 1.2 [2/1] [U_]
      [>....................]  recovery =  1.3% (1001728/73333760) finish=4.8min speed=250432K/sec
      
unused devices: <none>
```

2、等待重建完毕后，再扩容另外一块磁盘并加入

```
Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 vdc[3] vdb[2]
      73333760 blocks super 1.2 [2/2] [UU]

unused devices: <none>

Every 2.0s: cat /proc/mdstat                                                              VM-2-2-ubuntu: Fri May  9 11:42:12 2025

Personalities : [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 vdb[2] vdc[3]
      73333760 blocks super 1.2 [2/2] [UU]

unused devices: <none>
```

3、扩容Raid

```
mdadm --grow /dev/md0 --size=max
```

4、扩容文件系统

```

```