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raid 创建
使用mdadm创建raid，简单用法如下:
-l 用于指定创建的raid方式
| 参数简写 | 完整写法 | 说明 |
|---|---|---|
| -C | --create | 从未使用的设备创建新阵列 |
| -a | --auto=yes | 决定建立后面接的软体磁盘阵列设备，亦即/ dev/md0的，/ dev/md1上 |
| -n | --raid-devices=N | 使用几个磁盘 (partition) 作为磁盘阵列的设备 |
| -l | --level=[0,1,4,5,6,10] | 设置磁盘阵列的等级，常用 0,1,4,5,6,10 |
1. 添加两块硬盘
新增两块硬盘，使用fdisk -l查看新增的硬盘，新增了 /dev/sdb 、/dev/sdc
sh
[root@moujun ~]# fdisk -l
Disk /dev/sda: 107.4 GB, 107374182400 bytes, 209715200 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a9b3d
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 2099199 1048576 83 Linux
/dev/sda2 2099200 209715199 103808000 8e Linux LVM
Disk /dev/mapper/centos-root: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-swap: 4160 MB, 4160749568 bytes, 8126464 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/centos-home: 48.4 GB, 48444211200 bytes, 94617600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
[root@moujun ~]#2. 创建raid1
2.1 resync非常慢
提前说明这个，防止出现问题无法解决,查看以下两个文件，得知默认的最大速度：200000，最小速度：1000
cat /proc/sys/dev/raid/speed_limit_max
cat /proc/sys/dev/raid/speed_limit_min
将最小速度设置大点，可以有效解决同步慢的问题 ，将其设置到了150MB/s
echo 150000 > /proc/sys/dev/raid/speed_limit_min
2.2 创建raid1
创建不同类型的raid，仅需 修改 -l raid方式，-n参数设置磁盘数量，以及最后添加具体硬盘
sh
[root@moujun ~]# mdadm -C /dev/md1 -ayes -l1 -n2 /dev/sd[bc]
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/md1 started.
[root@moujun ~]#查看创建进度cat /proc/mdstat，等待resync完成
sh
[root@moujun ~]# cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sdc[1] sdb[0]
20954112 blocks super 1.2 [2/2] [UU]
[==>..................] resync = 13.3% (2800128/20954112) finish=1.5min speed=200009K/sec
unused devices: <none>
[root@moujun ~]#输入 mdadm -D /dev/md*命令查看相关信息
sh
[root@moujun ~]# mdadm -D /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Sun Mar 3 19:41:31 2024
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 : Sun Mar 3 19:43:16 2024
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Consistency Policy : resync
Name : moujun.top:1 (local to host moujun.top)
UUID : 67c00e23:ab70e9d7:99efe3df:48cc3421
Events : 17
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc
[root@moujun ~]#或者 mdadm --detail --scan 简写 mdadm -Ds
sh
[root@moujun ~]# mdadm --detail --scan
ARRAY /dev/md1 metadata=1.2 name=moujun.top:1 UUID=67c00e23:ab70e9d7:99efe3df:48cc3421创建包含 RAID 信息的配置文件
根据输出新增/etc/mdadm.conf文件内容：
ARRAY /dev/md/* level=raid1 num-devices=2 UUID={uuid}
go
# mdadm.conf written out by anaconda
MAILADDR root
AUTO +imsm +1.x -all
ARRAY /dev/md/1 level=raid1 num-devices=2 UUID=9f8ad06c:da23d88f:2a209233:9fce51f93. 格式化raid阵列
需要对磁盘进行格式化，根据系统要求进行格式化：ext4、 xfs
3.1 ext4格式化
命令格式：mkfs.ext4 -T largefile /dev/md1 , -T largefile 是快速格式化
sh
[root@moujun ~]# mkfs.ext4 -T largefile /dev/md1
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)m'k
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
20480 inodes, 5238528 blocks
261926 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
160 block groups
32768 blocks per group, 32768 fragments per group
128 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@moujun ~]#3.2 xfs格式化
命令格式：mkfs.xfs -f /dev/md1
-f :磁盘已被格式化，强制覆盖原有数据进行格式（丢失数据）
sh
[root@moujun ~]# mkfs.xfs -f /dev/md1
meta-data=/dev/md1 isize=512 agcount=4, agsize=1309632 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=5238528, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@moujun ~]#4. 挂载磁盘【可选】
注意
如果当前raid是需要lvm的，请跳过此操作
4.1 临时挂载
sh
mount /dev/md1 /mnt/raid/4.2 永久挂载
参数说明：
md
设备 挂载点 文件系统类型 挂载参数 是否备份 是否检测
/dev/sdc /data ext4 defaults 0 0在/etc/fstab文件中添加挂载信息
go
# /etc/fstab
# Created by anaconda on Mon Feb 19 02:16:44 2024
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root / xfs defaults 0 0
UUID=36410410-ab0e-42ad-a762-c9be30da02fa /boot xfs defaults 0 0
/dev/mapper/centos-home /home xfs defaults 0 0
/dev/mapper/centos-swap swap swap defaults 0 0
/dev/md1 /mnt/raid xfs defaults 0 05. 硬盘故障替换
仅举例raid1场景，其他场景请参考从场景做法
模拟raid1 中某块磁盘故障
sh[root@moujun ~]# mdadm -f /dev/md1 /dev/sdc mdadm: set /dev/sdc faulty in /dev/md1查看阵列详情
sh[root@moujun ~]# mdadm -D /dev/md1 /dev/md1: Version : 1.2 Creation Time : Mon Mar 4 09:06:29 2024 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 : Mon Mar 4 09:58:41 2024 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 1 Spare Devices : 0 Consistency Policy : resync Name : moujun.top:1 (local to host moujun.top) UUID : d1c6cbe0:1cb73de2:293c4671:a8269ef6 Events : 49 Number Major Minor RaidDevice State 1 8 16 1 active sync /dev/sdb 2 8 32 - faulty /dev/sdc [root@moujun ~]#移除故障的硬盘,仅剩一块盘
sh[root@moujun ~]# mdadm -r /dev/md1 /dev/sdc mdadm: hot removed /dev/sdc from /dev/md1 您在 /var/spool/mail/root 中有新邮件 [root@moujun ~]# mdadm -D /dev/md1 /dev/md1: Version : 1.2 Creation Time : Mon Mar 4 09:06:29 2024 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 : Mon Mar 4 10:01:29 2024 State : clean, degraded Active Devices : 1 Working Devices : 1 Failed Devices : 0 Spare Devices : 0 Consistency Policy : resync Name : moujun.top:1 (local to host moujun.top) UUID : d1c6cbe0:1cb73de2:293c4671:a8269ef6 Events : 50 Number Major Minor RaidDevice State 1 8 16 1 active sync /dev/sdb [root@moujun ~]#添加新的硬盘
sh[root@moujun ~]# mdadm -a /dev/md1 /dev/sdc mdadm: added /dev/sdc [root@moujun ~]#查看阵列详情，发现新增的盘显示
spare rebuildin,表示正在重建，等待重建完成显示active sync表示恢复正常sh[root@moujun ~]# mdadm -D /dev/md1 /dev/md1: Version : 1.2 Creation Time : Mon Mar 4 09:06:29 2024 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 : Mon Mar 4 10:03:08 2024 State : clean, degraded, recovering Active Devices : 1 Working Devices : 2 Failed Devices : 0 Spare Devices : 1 Consistency Policy : resync Rebuild Status : 8% complete Name : moujun.top:1 (local to host moujun.top) UUID : d1c6cbe0:1cb73de2:293c4671:a8269ef6 Events : 53 Number Major Minor RaidDevice State 2 8 32 0 spare rebuilding /dev/sdc 1 8 16 1 active sync /dev/sdb [root@moujun ~]#