LVM实现逻辑卷镜像
本文系统 Centos 6.5 x64
LVM的镜像功能，有点儿类似于Raid1，即多块儿磁盘互相同步，确保资料不会丢失。
1、在此添加4块物理硬盘，每块2G空间
2、将sdb、sdc、sdd、sde 创建物理卷，将sdb、sdc、sdd 添加卷组到vmTest
[root@node4 ~]# pvcreate /dev/sdb Physical volume "/dev/sdb" successfully created [root@node4 ~]# pvcreate /dev/sdc Physical volume "/dev/sdc" successfully created [root@node4 ~]# pvcreate /dev/sdd Physical volume "/dev/sdd" successfully created [root@node4 ~]# pvcreate /dev/sde Physical volume "/dev/sde" successfully created
[root@node4 ~]# vgcreate vgTest /dev/sdb /dev/sdc /dev/sdd Volume group "vgTest" successfully created [root@node4 ~]#
3、创建逻辑卷
[root@node4 ~]# lvcreate -L 1G -m1 -n lvTest vgTest /dev/sdb /dev/sdc /dev/sdd Logical volume "lvTest" created
查看lvs信息
[root@node4 ~]# lvs -a -o +devices LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0) lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186) lvTest vgTest mwi-a-m--- 1.00g lvTest_mlog 100.00 lvTest_mimage_0(0),lvTest_mimage_1(0) [lvTest_mimage_0] vgTest iwi-aom--- 1.00g /dev/sdb(0) [lvTest_mimage_1] vgTest iwi-aom--- 1.00g /dev/sdc(0) [lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sdd(0)
LVM镜像需要用到-m1参数，从上面可以看出，/dev/sdb和/dev/sdc互为镜像，而/dev/sdd作为日志存储使用
4、格式化分区，在逻辑卷上创建一个文件。对/dev/sdc进行破坏。
[root@node4 ~]# mkfs.ext4 /dev/vgTest/lvTest mke2fs 1.41.12 (17-May-2010) 文件系统标签= 操作系统:Linux 块大小=4096 (log=2) 分块大小=4096 (log=2) Stride=0 blocks, Stripe width=0 blocks 65536 inodes, 262144 blocks 13107 blocks (5.00%) reserved for the super user 第一个数据块=0 Maximum filesystem blocks=268435456 8 block groups 32768 blocks per group, 32768 fragments per group 8192 inodes per group Superblock backups stored on blocks: 32768, 98304, 163840, 229376 正在写入inode表: 完成 Creating journal (8192 blocks): 完成 Writing superblocks and filesystem accounting information: 完成 This filesystem will be automatically checked every 31 mounts or 180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@node4 ~]# dd if=/dev/zero of=/dev/sdc count=10 bs=20M 记录了10+0 的读入 记录了10+0 的写出 209715200字节(210 MB)已复制，2.08666 秒，101 MB/秒 [root@node4 ~]# lvs -a -o +devices Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X. LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0) lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186) lvTest vgTest mwi-a-m-p- 1.00g lvTest_mlog 100.00 lvTest_mimage_0(0),lvTest_mimage_1(0) [lvTest_mimage_0] vgTest iwi-aom--- 1.00g /dev/sdb(0) [lvTest_mimage_1] vgTest iwi-aom-p- 1.00g unknown device(0) [lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sdd(0) [root@node4 ~]# lvscan Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X. ACTIVE '/dev/vgTest/lvTest' [1.00 GiB] inherit ACTIVE '/dev/VolGroup/lv_root' [8.54 GiB] inherit ACTIVE '/dev/VolGroup/lv_swap' [992.00 MiB] inherit [root@node4 ~]#
重新挂载逻辑卷，确认文件可以正常读取
[root@node4 ~]# mkdir /lvmTest [root@node4 ~]# mount /dev/vgTest/lvTest /lvmTest/ [root@node4 ~]# cd /lvmTest/ [root@node4 lvmTest]# ls lost+found [root@node4 lvmTest]# echo "ac" > ac [root@node4 lvmTest]# cat ac ac [root@node4 lvmTest]#
将卷组中坏掉的物理卷（/dev/sdc）移除：
[root@node4 lvmTest]# vgdisplay Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X. --- Volume group --- VG Name vgTest System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 3 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 1 Max PV 0 Cur PV 3 Act PV 2 VG Size 5.99 GiB PE Size 4.00 MiB Total PE 1533 Alloc PE / Size 513 / 2.00 GiB Free PE / Size 1020 / 3.98 GiB VG UUID 1qzO3A-Tjvi-by9l-Oq49-byz3-tIkx-rfSqex
[root@node4 lvmTest]# vgreduce --removemissing --force vgTest Couldn't find device with uuid zecO8D-2Suc-rnmK-a2Z7-6613-Zy1X-whVS0X. Wrote out consistent volume group vgTest [root@node4 lvmTest]#
5、向卷组中加入新的物理卷（/dev/sde）：
[root@node4 lvmTest]# vgextend vgTest /dev/sde Volume group "vgTest" successfully extended [root@node4 lvmTest]#
6、进行数据恢复（过程中无须解除逻辑卷的挂载）
[root@node4 lvmTest]# lvconvert -m1 /dev/vgTest/lvTest /dev/sdb /dev/sdd /dev/sde vgTest/lvTest: Converted: 0.0% vgTest/lvTest: Converted: 100.0% [root@node4 lvmTest]# lvs -a -o +devices LV VG Attr LSize Pool Origin Data% Move Log Cpy%Sync Convert Devices lv_root VolGroup -wi-ao---- 8.54g /dev/sda2(0) lv_swap VolGroup -wi-ao---- 992.00m /dev/sda2(2186) lvTest vgTest mwi-aom--- 1.00g lvTest_mlog 100.00 lvTest_mimage_0(0),lvTest_mimage_1(0) [lvTest_mimage_0] vgTest iwi-aom--- 1.00g /dev/sdb(0) [lvTest_mimage_1] vgTest iwi-aom--- 1.00g /dev/sdd(0) [lvTest_mlog] vgTest lwi-aom--- 4.00m /dev/sde(0)
7、核实原数据
[root@node4 lvmTest]# cat ac ac [root@node4 lvmTest]# echo "abcde" >> ac [root@node4 lvmTest]# cat ac ac abcde [root@node4 lvmTest]#
[root@node4 lvmTest]# lvdisplay --- Logical volume --- LV Path /dev/vgTest/lvTest LV Name lvTest VG Name vgTest LV UUID a8kDmI-R3ls-SfKJ-qx3d-1Tbb-wPAd-TJcQfn LV Write Access read/write LV Creation host, time node4.lansgg.com, 2015-09-10 20:50:41 +0800 LV Status available # open 1 LV Size 1.00 GiB Current LE 256 Mirrored volumes 2 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:5