无需救援模式,新添加硬盘并在运行的LVM上设置软RAID1

给手头上的一台独服新上一块硬盘并设置软raid1作备份,原先并没有设置软raid。

百度上的教程都是完全复制粘贴没找到一步到位的。

Google了会并搞定了,记录下。

由于涉及到数据问题,强烈建议先自己本地开个虚拟机测试成功了再转移到真正需要操作的环境。

参考资料:https://www.howtoforge.com/how-to-set-up-software-raid1-on-a-running-lvm-system-incl-grub-configuration-centos-5.3 和 Google

测试的系统为centos7,使用grub2.


设置raid前的系统分区环境:

  • /dev/sda1/boot partition, ext4;
  • /dev/sda2: Linux LVM 包含根目录
  • /dev/sdb: 未分区的新硬盘

设置完raid理想分区环境是:

  • /dev/md0 (made up of /dev/sda1 and /dev/sdb1): /boot partition, ext4;
  • /dev/md1 (made up of /dev/sda2 and /dev/sdb2): LVM , 包含 /
df -h

[root@server1 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
8.6G  1.4G  6.8G  17% /
/dev/sda1              99M   13M   82M  14% /boot
tmpfs                 250M     0  250M   0% /dev/shm
[root@server1 ~]#

fdisk -l

[root@server1 ~]# fdisk -l

Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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        1305    10377990   8e  Linux LVM

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn’t contain a valid partition table
[root@server1 ~]#

pvdisplay

[root@server1 ~]# pvdisplay
/dev/hdc: open failed: No medium found
— Physical volume —
PV Name               /dev/sda2
VG Name               VolGroup00
PV Size               9.90 GB / not usable 22.76 MB
Allocatable           yes (but full)
PE Size (KByte)       32768
Total PE              316
Free PE               0
Allocated PE          316
PV UUID               aikFEP-FB15-nB9C-Nfq0-eGMG-hQid-GOsDuj

[root@server1 ~]#

vgdisplay

[root@server1 ~]# vgdisplay
/dev/hdc: open failed: No medium found
— Volume group —
VG Name               VolGroup00
System ID
Format                lvm2
Metadata Areas        1
Metadata Sequence No  3
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                2
Open LV               2
Max PV                0
Cur PV                1
Act PV                1
VG Size               9.88 GB
PE Size               32.00 MB
Total PE              316
Alloc PE / Size       316 / 9.88 GB
Free  PE / Size       0 / 0
VG UUID               ZPvC10-cN09-fI0S-Vc8l-vOuZ-wM6F-tlz0Mj

[root@server1 ~]#

lvdisplay

请记下当前系统使用的VG Name(卷组名)和 LV name(逻辑卷名)

[root@server1 ~]# lvdisplay
/dev/hdc: open failed: No medium found
— Logical volume —
LV Name                /dev/VolGroup00/LogVol00
VG Name                VolGroup00
LV UUID                vYlky0-Ymx4-PNeK-FTpk-qxvm-PmoZ-3vcNTd
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                8.88 GB
Current LE             284
Segments               1
Allocation             inherit
Read ahead sectors     auto
– currently set to     256
Block device           253:0

— Logical volume —
LV Name                /dev/VolGroup00/LogVol01
VG Name                VolGroup00
LV UUID                Ml9MMN-DcOA-Lb6V-kWPU-h6IK-P0ww-Gp9vd2
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                1.00 GB
Current LE             32
Segments               1
Allocation             inherit
Read ahead sectors     auto
– currently set to     256
Block device           253:1

[root@server1 ~]#


现在开始安装mdadm

yum install mdadm
modprobe linear
modprobe multipath
modprobe raid0
modprobe raid1
modprobe raid5
modprobe raid6
modprobe raid10

干完这些,运行:

cat /proc/mdstat

输出大致应该是这样子的:

[root@server1 ~]# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
unused devices: <none>
[root@server1 ~]#


开始处理新硬盘sdb

我们需要将旧硬盘sda里所有的数据全部转移到新硬盘sdb里

首先,我们需要将旧硬盘的分区表复制到新硬盘里。

sfdisk -d /dev/sda | sfdisk /dev/sdb

输出大致为:

[root@server1 ~]# sfdisk -d /dev/sda | sfdisk /dev/sdb
Checking that no-one is using this disk right now …
OK

Disk /dev/sdb: 1305 cylinders, 255 heads, 63 sectors/track

sfdisk: ERROR: sector 0 does not have an msdos signature
/dev/sdb: unrecognized partition table type
Old situation:
No partitions found
New situation:
Units = sectors of 512 bytes, counting from 0

Device Boot    Start       End   #sectors  Id  System
/dev/sdb1   *        63    208844     208782  83  Linux
/dev/sdb2        208845  20964824   20755980  8e  Linux LVM
/dev/sdb3             0         –          0   0  Empty
/dev/sdb4             0         –          0   0  Empty
Successfully wrote the new partition table

Re-reading the partition table …

If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes:  dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)
[root@server1 ~]#

然后使用fdisk -l 确认现在的分区表:

root@server1 ~]# fdisk -l

Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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        1305    10377990   8e  Linux LVM

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          13      104391   83  Linux
/dev/sdb2              14        1305    10377990   8e  Linux LVM
[root@server1 ~]#

此时sda和sdb应有相同的分区表。

然后,我们需要把sdb上的分区变成 Linux raid autodetect类型

fdisk /dev/sdb
[root@server1 ~]# fdisk /dev/sdb

The number of cylinders for this disk is set to 1305.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)
Command (m for help): <-- t (输入t)
Partition number (1-4): <-- 1  (输入1)
Hex code (type L to list codes): <-- fd (输入fd)
Changed system type of partition 1 to fd (Linux raid autodetect)

Command (m for help): <-- t (输入t)
Partition number (1-4): <-- 2 (输入2)
Hex code (type L to list codes): <-- fd (输入fd)
Changed system type of partition 2 to fd (Linux raid autodetect)

Command (m for help): <-- w (输入w)#保存
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@server1 ~]#
fdisk -l

确认sdb上的分区都为Linux raid autodetect

[root@server1 ~]# fdisk -l

Disk /dev/sda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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        1305    10377990   8e  Linux LVM

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1          13      104391   fd  Linux raid autodetect
/dev/sdb2              14        1305    10377990   fd  Linux raid autodetect
[root@server1 ~]#

然后,我们需要清除硬盘上以前的raid记录:

mdadm --zero-superblock /dev/sdb1
mdadm --zero-superblock /dev/sdb2

如果硬盘上以前没有raid记录的话输出大概是():

[root@server1 ~]# mdadm –zero-superblock /dev/sdb1
mdadm: Unrecognised md component device – /dev/sdb1
[root@server1 ~]#

这是正常的不用担心。如果有记录的话应该是什么都不显示。

现在,我们就可以开始创建 RAID 阵列 /dev/md0 和 /dev/md1/dev/sdb1 将会被包含进 /dev/md0 ,/dev/sdb2 会被包含进 /dev/md1/dev/sda1 和 /dev/sda2现在还不能被添加 (数据还没移!!!), 所以,我们现在用missing 来代替它们:

mdadm --create /dev/md0 --level=1 --raid-disks=2 missing /dev/sdb1
mdadm --create /dev/md1 --level=1 --raid-disks=2 missing /dev/sdb2

查看刚刚创建的raid

cat /proc/mdstat

[root@server1 ~]# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sdb2[1]
10377920 blocks [2/1] [_U]

md0 : active raid1 sdb1[1]
104320 blocks [2/1] [_U]

 

由于md0会被用作/boot,所以我们需要把它格式化成与当前/boot相同的格式。这里是ext4

mkfs.ext4 /dev/md0

由于md1会被用作LVM, 我们需要把它格式化成物理卷

pvcreate /dev/md1

然后,我们需要把 /dev/md1 添加到现有的卷组 VolGroup00里:

vgextend VolGroup00 /dev/md1

查看当前卷组情况:

pvdisplay

输出大致为:

[root@server1 ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               9.90 GB / not usable 22.76 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              316
  Free PE               0
  Allocated PE          316
  PV UUID               aikFEP-FB15-nB9C-Nfq0-eGMG-hQid-GOsDuj

  --- Physical volume ---
  PV Name               /dev/md1
  VG Name               VolGroup00
  PV Size               9.90 GB / not usable 22.69 MB
  Allocatable           yes
  PE Size (KByte)       32768
  Total PE              316
  Free PE               316
  Allocated PE          0
  PV UUID               u6IZfM-5Zj8-kFaG-YN8K-kjAd-3Kfv-0oYk7J

[root@server1 ~]#
vgdisplay

输出大致为:

[root@server1 ~]# vgdisplay
  --- Volume group ---
  VG Name               VolGroup00
  System ID
  Format                lvm2
  Metadata Areas        2
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                2
  Open LV               2
  Max PV                0
  Cur PV                2
  Act PV                2
  VG Size               19.75 GB
  PE Size               32.00 MB
  Total PE              632
  Alloc PE / Size       316 / 9.88 GB
  Free  PE / Size       316 / 9.88 GB
  VG UUID               ZPvC10-cN09-fI0S-Vc8l-vOuZ-wM6F-tlz0Mj

[root@server1 ~]#

现在,我们需要创建新的/etc/mdadm.conf

mdadm –verbose –detail -scan > /etc/mdadm.conf

查看madadm.conf

cat /etc/mdadm.conf

输出大致为(很可能有区别,uuid每个人都不一样):

ARRAY /dev/md0 level=raid1 num-devices=2 UUID=0a96be0f:bf0f4631:a910285b:0f337164
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=f9e691e2:8d25d314:40f42444:7dbe1da1

现在,我们可以把现有的逻辑卷数据复制到sdb2上了:

pvmove /dev/sda2 /dev/md1

然后,把sda2移除当前使用的卷组:

vgreduce VolGroup00 /dev/sda2
pvremove /dev/sda2

现在的物理卷情况:

pvdisplay
[root@server1 ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/md1
  VG Name               VolGroup00
  PV Size               9.90 GB / not usable 22.69 MB
  Allocatable           yes (but full)
  PE Size (KByte)       32768
  Total PE              316
  Free PE               0
  Allocated PE          316
  PV UUID               u6IZfM-5Zj8-kFaG-YN8K-kjAd-3Kfv-0oYk7J

[root@server1 ~]#

然后,我们就可以把sda2和sdb2合并,变成raid1阵列md1

fdisk /dev/sda
[root@server1 ~]# fdisk /dev/sda

The number of cylinders for this disk is set to 1305.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): <-- t (输入t)
Partition number (1-4): <-- 2 (输入2)
Hex code (type L to list codes): <-- fd (输入fd)
Changed system type of partition 2 to fd (Linux raid autodetect)

Command (m for help): <-- w (输入w)#保存
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
[root@server1 ~]#
mdadm --add /dev/md1 /dev/sda2

现在,我们可以查看当前阵列信息:

cat /proc/mdstat
[root@server1 ~]# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sda2[2] sdb2[1]
      10377920 blocks [2/1] [_U]
      [====>................]  recovery = 23.4% (2436544/10377920) finish=2.0min speed=64332K/sec

md0 : active raid1 sdb1[1]
      104320 blocks [2/1] [_U]

unused devices: <none>
[root@server1 ~]#

可以看到系统正在自动把sda2和sdb2的数据同步,可能需要相当久的一段时间

可以使用

watch cat /proc/mdstat

来实时监视进度

同步完成后, 我们需要建立新的initramfs来确保系统可以正常启动。
这里使用的是grub2,grub或者extlinux请参考grub2并自行根据情况修改/boot里面各种的配置文件并安装。

首先运行

mdadm --verbose --detail -scan

记下当前所有md设备的uuid

 

然后修改

 /etc/default/grub

在GRUB_CMDLINE_LINUX行里添加

rd.md.uuid="md0的uuid(删掉双引号)" rd.md.uuid="md1的uuid(删掉双引号)" 

保存退出后运行

grub2-mkconfig -o /boot/grub2/grub.cfg

然后运行

dracut --regenerate-all -fv --mdadmconf --fstab --add=mdraid --add-driver="raid1 raid10 raid456"

完成后再重新给两个硬盘安装grub2

grub2-install /dev/sda
grub2-install /dev/sdb

然后就可以运行reboot重启了

正常来说重启正常

如果重启后发现系统无法自动组合raid设备为md*的话可以等待超时后initramfs命令行里运行

mdadm --assemble --scan --run --auto=yes
lvm vgchange -ay
exit

来手动组合raid设备为md*并识别lvm然后手动启动。


重启正常后,可以着手处理md0了。

mkdir /mnt/md0
mount /dev/md0 /mnt/md0

然后,把我们当前的boot分区里的所有内容复制到md0里面去

cd /boot
cp -dpRx . /mnt/md0

然后修改fstab和mtab(如果能的话)

fstab:

修改/boot挂载的设备为/dev/md0


/dev/VolGroup00/LogVol00 /                       ext3    defaults        1 1
/dev/md0             /boot                   ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/VolGroup00/LogVol01 swap                    swap    defaults        0 0

mtab:

同上

/dev/mapper/VolGroup00-LogVol00 / ext3 rw 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
devpts /dev/pts devpts rw,gid=5,mode=620 0 0
/dev/md0 /boot ext3 rw 0 0
tmpfs /dev/shm tmpfs rw 0 0
none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0
sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw 0 0

然后我们就可以把/dev/sda1合并到md0里了

fdisk /dev/sda
[root@server1 ~]# fdisk /dev/sda

The number of cylinders for this disk is set to 1305.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): <-- t (输入t)
Partition number (1-4): <-- 1 (输入1)
Hex code (type L to list codes): <-- fd (输入fd)
Changed system type of partition 1 to fd (Linux raid autodetect)

Command (m for help): <-- w (输入w)
The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
[root@server1 ~]#

然后把sda1加到md0里:

mdadm --add /dev/md0 /dev/sda1
cat /proc/mdstat

应该很快就同步完了,输出大概是:

[root@server1 ~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[0] sdb1[1]
      104320 blocks [2/2] [UU]

md1 : active raid1 sdb2[1] sda2[0]
      10377920 blocks [2/2] [UU]

unused devices: <none>
[root@server1 ~]#

然后更新一下mdadm.conf

mdadm --verbose --detail -scan > /etc/mdadm.conf

然后以防万一,重新建立一遍initramfs

dracut --regenerate-all -fv --mdadmconf --fstab --add=mdraid --add-driver="raid1 raid10 raid456"

然后就是见证奇迹的时刻了,reboot重启。

reboot

不出意外应该就设置完毕了。

 

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