LVM逻辑卷管理--在线扩容、逻辑卷与卷组容量缩减、逻辑卷快照
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LVM逻辑卷管理
公司生产环境中使用了LVM逻辑卷管理，所以今天花时间整理一下。通过LVM技术整合所有的磁盘资源进行分区，然后创建PV物理卷形成一个资源池，再划分卷组，最后在卷组上创建不同的逻辑卷，继而初始化逻辑卷，挂载到系统中使用。LVM对比传统硬盘存储的优点1、 统一管理：整合多个磁盘或分区形成一个资源池2、 灵活性：可以使用不同磁盘、不同分区来组成一个逻辑卷3、 可伸缩性：逻辑卷和卷组的容量都可以使用命令来扩展或者缩减，且不会影响破坏原有数据，支持磁盘热插拔。4、 支持热插拔5、 支持在线数据移动6、 设备命名方便7、 镜像卷：可以很方便的做数据镜像8、 卷快照：把逻辑卷中的数据快照保存到新的逻辑卷进行备份逻辑分区与逻辑卷的区别逻辑卷与逻辑分区不是同一概念，逻辑分区容量大小不能改变；逻辑卷容量大小可以改变（基于物理卷和卷组之上的逻辑卷）；逻辑卷管理器（LVM）可以更轻松的管理磁盘空间（整合的磁盘池）LVM原理图Physical volume (PV物理卷)、Volume group (VG卷组)、Logical volume(LV逻辑卷)，通过图解更容易读懂物理磁盘、磁盘分区、物理卷、卷组、逻辑卷之间的关系（个人理解，仅供参考）
测试环境
内核LVM1版本需要2.4（包括）以后的内核支持；LVM2需要2.6（包括）以后的内核版本支持。[root@localhost ~]# cat /etc/redhat-release CentOS Linux release 7.4.1708 (Core) [root@localhost ~]# uname -r3.10.0-693.el7.x86_64
新添加两块磁盘
[root@localhost ~]# fdisk -lDisk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x0000457f Device Boot Start End Blocks Id System/dev/sda1 * 2048 2099199 1048576 83 Linux/dev/sda2 2099200 41943039 19921920 8e Linux LVMDisk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/centos-root: 18.2 GB, 18249416704 bytes, 35643392 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytes
磁盘分区
第一块磁盘[root@localhost ~]# fdisk /dev/sdbCommand (m for help): nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): pPartition number (1-4, default 1): First sector (2048-41943039, default 2048): Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +10GPartition 1 of type Linux and of size 10 GiB is setCommand (m for help): nPartition type: p primary (1 primary, 0 extended, 3 free) e extendedSelect (default p): p #主分区Partition number (2-4, default 2): First sector (20973568-41943039, default 20973568): Using default value 20973568Last sector, +sectors or +size{K,M,G} (20973568-41943039, default 41943039): Using default value 41943039Partition 2 of type Linux and of size 10 GiB is setCommand (m for help): p #第一块磁盘划分两个主分区Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0xfba75d9e Device Boot Start End Blocks Id System/dev/sdb1 2048 20973567 10485760 83 Linux/dev/sdb2 20973568 41943039 10484736 83 LinuxCommand (m for help): t #做LVM管理，需要修改分区类型为Linux LVMPartition number (1,2, default 2): 1Hex code (type L to list all codes): 8eChanged type of partition 'Linux' to 'Linux LVM'Command (m for help): tPartition number (1,2, default 2): 2Hex code (type L to list all codes): 8eChanged type of partition 'Linux' to 'Linux LVM'Command (m for help): pDisk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0xfba75d9e Device Boot Start End Blocks Id System/dev/sdb1 2048 20973567 10485760 8e Linux LVM/dev/sdb2 20973568 41943039 10484736 8e Linux LVMCommand (m for help): w #保存分区信息The partition table has been altered!Calling ioctl() to re-read partition table.Syncing disks.告诉内核[root@localhost ~]# partprobe /dev/sdb #更新内核分区表[root@localhost ~]# ls -l /dev/sdb*brw-rw----. 1 root disk 8, 16 Oct 13 11:30 /dev/sdbbrw-rw----. 1 root disk 8, 17 Oct 13 11:30 /dev/sdb1brw-rw----. 1 root disk 8, 18 Oct 13 11:30 /dev/sdb2[root@localhost ~]# 第二块磁盘
创建一个主分区和一个逻辑分区，用来测试扩展分区和逻辑分区是否能够创建PV物理卷并加入VG卷组，实验证明，扩展分区是无法创建PV和加入VG，主分区和逻辑分区可以。[root@localhost ~]# fdisk /dev/sdcWelcome to fdisk (util-linux 2.23.2).Changes will remain in memory only, until you decide to write them.Be careful before using the write command.Device does not contain a recognized partition tableBuilding a new DOS disklabel with disk identifier 0x5d61bb7c.Command (m for help): nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): p #主分区Partition number (1-4, default 1): First sector (2048-41943039, default 2048): Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +10GPartition 1 of type Linux and of size 10 GiB is setCommand (m for help): nPartition type: p primary (1 primary, 0 extended, 3 free) e extendedSelect (default p): e #扩展分区，要创建扩展分区之后，才能创建逻辑分区；扩展分区只能创建一个，分区表支持创建最多四分主分区，如果想要创建4个以上的分区，必须创建扩展分区，然后创建逻辑分区Partition number (2-4, default 2): First sector (20973568-41943039, default 20973568): Using default value 20973568Last sector, +sectors or +size{K,M,G} (20973568-41943039, default 41943039): Using default value 41943039Partition 2 of type Extended and of size 10 GiB is setCommand (m for help): nPartition type: p primary (1 primary, 1 extended, 2 free) l logical (numbered from 5)Select (default p): l #创建逻辑分区Adding logical partition 5First sector (20975616-41943039, default 20975616): Using default value 20975616Last sector, +sectors or +size{K,M,G} (20975616-41943039, default 41943039): Using default value 41943039Partition 5 of type Linux and of size 10 GiB is setCommand (m for help): pDisk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x5d61bb7c Device Boot Start End Blocks Id System/dev/sdc1 2048 20973567 10485760 83 Linux/dev/sdc2 20973568 41943039 10484736 5 Extended/dev/sdc5 20975616 41943039 10483712 83 LinuxCommand (m for help): t #修改分区类型Partition number (1,2,5, default 5): 1Hex code (type L to list all codes): 8eChanged type of partition 'Linux' to 'Linux LVM'Command (m for help): tPartition number (1,2,5, default 5): 2 Hex code (type L to list all codes): 8eYou cannot change a partition into an extended one or vice versa.Delete it first.Type of partition 2 is unchanged: ExtendedCommand (m for help): tPartition number (1,2,5, default 5): 5Hex code (type L to list all codes): 8eChanged type of partition 'Linux' to 'Linux LVM'Command (m for help): pDisk /dev/sdc: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0x5d61bb7c Device Boot Start End Blocks Id System/dev/sdc1 2048 20973567 10485760 8e Linux LVM/dev/sdc2 20973568 41943039 10484736 5 Extended/dev/sdc5 20975616 41943039 10483712 8e Linux LVMCommand (m for help): w #保存分区表信息The partition table has been altered!Calling ioctl() to re-read partition table.Syncing disks.[root@localhost ~]# partprobe /dev/sdc[root@localhost ~]# ls -l /dev/sdc*brw-rw----. 1 root disk 8, 32 Oct 13 11:35 /dev/sdcbrw-rw----. 1 root disk 8, 33 Oct 13 11:35 /dev/sdc1brw-rw----. 1 root disk 8, 34 Oct 13 11:35 /dev/sdc2brw-rw----. 1 root disk 8, 37 Oct 13 11:35 /dev/sdc5 创建PV、VG、LV
创建PV物理卷[root@localhost ~]# pvcreate /dev/sdc2 #sdc2是扩展分区，无法做成物理卷PV Device /dev/sdc2 not found (or ignored by filtering).[root@localhost ~]# pvcreate /dev/sdb1 #把sdb1做成物理卷PV，也可以用下面的写法，一次性把所有主分区或逻辑分区做成物理卷PV Physical volume "/dev/sdb1" successfully created.[root@localhost ~]# pvcreate /dev/sdb2 /dev/sdc1 /dev/sdc5 Physical volume "/dev/sdb2" successfully created. Physical volume "/dev/sdc1" successfully created. Physical volume "/dev/sdc5" successfully created.[root@localhost ~]# pvdisplay #查看物理卷详细信息 --- Physical volume --- PV Name /dev/sda2 VG Name centos PV Size <19.00 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 4863 Free PE 0 Allocated PE 4863 PV UUID 610jgI-z9pr-N5H1-R1Qv-jVMh-cMOD-2VKNm5 "/dev/sdb1" is a new physical volume of "10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdb1 VG Name PV Size 10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID l65LfK-FxkO-I8ux-0Lj6-jQB1-ev6d-jl4D8v "/dev/sdc1" is a new physical volume of "10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdc1 VG Name PV Size 10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID olFzUh-w2jf-sK32-i4lr-oYHP-zWTf-dKmgYw "/dev/sdc5" is a new physical volume of "<10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdc5 VG Name PV Size <10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID 54wYXO-sN3e-Lyc6-2ZQg-YMkH-6khg-TqbKOA "/dev/sdb2" is a new physical volume of "<10.00 GiB" --- NEW Physical volume --- PV Name /dev/sdb2 VG Name PV Size <10.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID aqkWHa-RIxf-15Y9-mgLw-x82r-thpL-kxzYhc[root@localhost ~]# pvs #显示所有的物理卷，大小都是10G（分区的时候分配的） PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <19.00g 0 /dev/sdb1 lvm2 --- 10.00g 10.00g /dev/sdb2 lvm2 --- <10.00g <10.00g /dev/sdc1 lvm2 --- 10.00g 10.00g /dev/sdc5 lvm2 --- <10.00g <10.00g
创建卷组
[root@localhost ~]# vgcreate VGtest1 /dev/sdb1 /dev/sdc1 #创建卷组1，卷组的PV物理卷，可以是不同磁盘，即整合了所有磁盘分区做成资源池 Volume group "VGtest1" successfully created[root@localhost ~]# vgcreate VGtest2 /dev/sdb2 /dev/sdc5 #创建卷组2 Volume group "VGtest2" successfully created[root@localhost ~]# vgs #显示所有卷组信息 VG #PV #LV #SN Attr VSize VFree VGtest1 2 0 0 wz--n- 19.99g 19.99g VGtest2 2 0 0 wz--n- 19.99g 19.99g centos 1 2 0 wz--n- <19.00g 0 [root@localhost ~]# vgdisplay #查看所有卷组的详细信息 --- Volume group --- VG Name centos 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 <19.00 GiB PE Size 4.00 MiB Total PE 4863 Alloc PE / Size 4863 / <19.00 GiB Free PE / Size 0 / 0 VG UUID FjdwU1-IYgt-Q6r2-uGm7-q1de-g0yh-EsGm64 --- Volume group --- VG Name VGtest1 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 1 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 19.99 GiB PE Size 4.00 MiB Total PE 5118 Alloc PE / Size 0 / 0 Free PE / Size 5118 / 19.99 GiB VG UUID pk62Bc-lRQW-iXim-VUng-PrIk-s9WR-10uctH --- Volume group --- VG Name VGtest2 System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 1 VG Access read/write VG Status resizable MAX LV 0 Cur LV 0 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 19.99 GiB PE Size 4.00 MiB Total PE 5118 Alloc PE / Size 0 / 0 Free PE / Size 5118 / 19.99 GiB VG UUID XsUyyE-1OSa-Xbno-L0W3-cL3E-XmeH-qb3QWW
创建逻辑卷
[root@localhost ~]# lvcreate -n LVtest1 -L 1G VGtest1 #-n表示创建逻辑卷名，-L表示分配逻辑卷的空间大小，VGtest1表示在卷组VGtest1上创建逻辑卷LVtest1 Logical volume "LVtest1" created.[root@localhost ~]# lvcreate -n LVtest2 -L 1G VGtest2 Logical volume "LVtest2" created.[root@localhost ~]# lvs #显示逻辑卷的信息（大小为1G，上面分配的） LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 -wi-a----- 1.00g LVtest2 VGtest2 -wi-a----- 1.00g root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# lvdisplay #显示逻辑卷的详细信息 --- Logical volume --- LV Path /dev/centos/swap LV Name swap VG Name centos LV UUID gS0ted-R1jU-NKWR-rpFb-quUd-Yu7w-c0VfGz LV Write Access read/write LV Creation host, time localhost, 2018-09-14 09:38:10 -0400 LV Status available # open 2 LV Size 2.00 GiB Current LE 512 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:1 --- Logical volume --- LV Path /dev/centos/root LV Name root VG Name centos LV UUID LTcnK5-ufCZ-5Cwx-Lpfi-Frgo-NMBm-OEE73C LV Write Access read/write LV Creation host, time localhost, 2018-09-14 09:38:10 -0400 LV Status available # open 1 LV Size <17.00 GiB Current LE 4351 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:0 --- Logical volume --- LV Path /dev/VGtest1/LVtest1 LV Name LVtest1 VG Name VGtest1 LV UUID PMv1Zv-WtJy-13v4-1GBc-5WaB-mcpk-f7dN22 LV Write Access read/write LV Creation host, time localhost.localdomain, 2018-10-13 11:48:28 -0400 LV Status available # open 0 LV Size 1.00 GiB Current LE 256 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:2 --- Logical volume --- LV Path /dev/VGtest2/LVtest2 LV Name LVtest2 VG Name VGtest2 LV UUID HCk2OB-3iVy-Ryma-rKeH-kIie-NYKr-ZVkiIf LV Write Access read/write LV Creation host, time localhost.localdomain, 2018-10-13 11:48:47 -0400 LV Status available # open 0 LV Size 1.00 GiB Current LE 256 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 8192 Block device 253:3会创建对应的目录和文件[root@localhost ~]# ls -l /dev/VGtest1/LVtest1 lrwxrwxrwx. 1 root root 7 Oct 13 11:48 /dev/VGtest1/LVtest1 -> ../dm-2[root@localhost ~]# ls -l /dev/ddisk/ dm-0 dm-1 dm-2 dm-3 dmmidi dri/ [root@localhost ~]# ls -l /dev/dm-2brw-rw----. 1 root disk 253, 2 Oct 13 11:48 /dev/dm-2
格式化LV逻辑卷
[root@localhost ~]# mke2fs -t ext4 /dev/VGtest1/LVtest1 #物理卷需要格式化之后才能使用，格式化为ext4格式mke2fs 1.42.9 (28-Dec-2013)Filesystem label=OS type: LinuxBlock size=4096 (log=2)Fragment size=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks65536 inodes, 262144 blocks13107 blocks (5.00%) reserved for the super userFirst data block=0Maximum filesystem blocks=2684354568 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376Allocating group tables: done Writing inode tables: done Creating journal (8192 blocks): doneWriting superblocks and filesystem accounting information: done[root@localhost ~]# mkfs.ext4 /dev/VGtest2/LVtest2 #也可以使用这种方式格式化mke2fs 1.42.9 (28-Dec-2013)Filesystem label=OS type: LinuxBlock size=4096 (log=2)Fragment size=4096 (log=2)Stride=0 blocks, Stripe width=0 blocks65536 inodes, 262144 blocks13107 blocks (5.00%) reserved for the super userFirst data block=0Maximum filesystem blocks=2684354568 block groups32768 blocks per group, 32768 fragments per group8192 inodes per groupSuperblock backups stored on blocks: 32768, 98304, 163840, 229376Allocating group tables: done Writing inode tables: done Creating journal (8192 blocks): doneWriting superblocks and filesystem accounting information: done
挂载LV逻辑卷
[root@localhost ~]# mkdir /appdata[root@localhost ~]# mkdir /applog[root@localhost ~]# mount /dev/VGtest1/LVtest1 /appdata #把LV逻辑卷挂载到实际的目录[root@localhost ~]# mount /dev/VGtest2/LVtest2 /applog[root@localhost ~]# df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/centos-root 17G 1.2G 16G 7% /devtmpfs 482M 0 482M 0% /devtmpfs 493M 0 493M 0% /dev/shmtmpfs 493M 6.8M 486M 2% /runtmpfs 493M 0 493M 0% /sys/fs/cgroup/dev/sda1 1014M 125M 890M 13% /boottmpfs 99M 0 99M 0% /run/user/0/dev/mapper/VGtest1-LVtest1 976M 2.6M 907M 1% /appdata/dev/mapper/VGtest2-LVtest2 976M 2.6M 907M 1% /applog[root@localhost ~]# mount |grep VGtest/dev/mapper/VGtest1-LVtest1 on /appdata type ext4 (rw,relatime,seclabel,data=ordered)/dev/mapper/VGtest2-LVtest2 on /applog type ext4 (rw,relatime,seclabel,data=ordered)永久挂载LV逻辑卷[root@localhost ~]# vim /etc/fstab ## /etc/fstab# Created by anaconda on Fri Sep 14 09:38:12 2018## 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 0UUID=944557a0-3f7c-434d-8202-c960db70b860 /boot xfs defaults 0 0/dev/mapper/centos-swap swap swap defaults 0 0/dev/VGtest1/LVtest1 /appdata ext4 defaults 0 0/dev/VGtest2/LVtest2 /applog ext4 defaults 0 0~~"/etc/fstab" 13L, 617C written [root@localhost ~]# mount -a #重新加载/etc/fstab文件
VG卷组扩容
新建一个PV物理卷，然后加入VG即可（fdisk创建分区->修改分区类型Linux LVM->向内核注册新分区->创建物理卷->把物理卷加入需要扩容的卷组）。发现卷组pv空间不够，我们需要扩大卷组空间，现在系统上新增了一块20G的硬盘/dev/sdc。[root@localhost ~]# fdisk /dev/sdd #把新添加的磁盘进行分区Welcome to fdisk (util-linux 2.23.2).Changes will remain in memory only, until you decide to write them.Be careful before using the write command.Device does not contain a recognized partition tableBuilding a new DOS disklabel with disk identifier 0xc29c0ac3.Command (m for help): nPartition type: p primary (0 primary, 0 extended, 4 free) e extendedSelect (default p): p #主分区Partition number (1-4, default 1): First sector (2048-41943039, default 2048): Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +5GPartition 1 of type Linux and of size 5 GiB is setCommand (m for help): t #修改分区类型Selected partition 1Hex code (type L to list all codes): 8eChanged type of partition 'Linux' to 'Linux LVM'Command (m for help): pDisk /dev/sdd: 21.5 GB, 21474836480 bytes, 41943040 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk label type: dosDisk identifier: 0xc29c0ac3 Device Boot Start End Blocks Id System/dev/sdd1 2048 10487807 5242880 8e Linux LVMCommand (m for help): w #保存分区信息The partition table has been altered!Calling ioctl() to re-read partition table.Syncing disks.[root@localhost ~]# partprobe /dev/sdd #更新内核分区表[root@localhost ~]# pvcreate /dev/sdd1 #创建物理卷PV Physical volume "/dev/sdd1" successfully created.[root@localhost ~]# pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <19.00g 0 /dev/sdb1 VGtest1 lvm2 a-- <10.00g <9.00g /dev/sdb2 VGtest2 lvm2 a-- <10.00g <9.00g /dev/sdc1 VGtest1 lvm2 a-- <10.00g <10.00g /dev/sdc5 VGtest2 lvm2 a-- <10.00g <10.00g /dev/sdd1 lvm2 --- 5.00g 5.00g[root@localhost ~]# vgextend VGtest1 /dev/sdd1 #扩展VG卷组容量，把物理卷加入卷组 Volume group "VGtest1" successfully extended[root@localhost ~]# vgs VG #PV #LV #SN Attr VSize VFree VGtest1 3 1 0 wz--n- <24.99g <23.99g VGtest2 2 1 0 wz--n- 19.99g 18.99g centos 1 2 0 wz--n- <19.00g 0 [root@localhost ~]# pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <19.00g 0 /dev/sdb1 VGtest1 lvm2 a-- <10.00g <9.00g /dev/sdb2 VGtest2 lvm2 a-- <10.00g <9.00g /dev/sdc1 VGtest1 lvm2 a-- <10.00g <10.00g /dev/sdc5 VGtest2 lvm2 a-- <10.00g <10.00g /dev/sdd1 VGtest1 lvm2 a-- <5.00g <5.00g LV逻辑卷扩容 (支持在线扩展)
在线将/dev/VGtest/LVtest1 扩展到4G，并且要求数据可以正常访问[root@localhost ~]# echo "this is a test for LVM" >/appdata/test[root@localhost ~]# cat /appdata/test #在挂载的逻辑卷里添加数据，用来测试在逻辑卷扩容是否会破坏原有数据this is a test for LVM[root@localhost ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 -wi-ao---- 1.00g LVtest2 VGtest2 -wi-ao---- 1.00g root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# lvextend -L +2G /dev/VGtest1/LVtest1 #扩容逻辑卷LVtest1，增加2G空间容量（从对应的卷组中划分空间容量） Size of logical volume VGtest1/LVtest1 changed from 1.00 GiB (256 extents) to 3.00 GiB (768 extents). Logical volume VGtest1/LVtest1 successfully resized.[root@localhost ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 -wi-ao---- 3.00g LVtest2 VGtest2 -wi-ao---- 1.00g root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# resize2fs /dev/VGtest1/LVtest1 #使用resize2fs命令来进行确认增加容量，前面的步骤只是初步分配，还不能实际使用，需要此步骤来确定实际分配使用resize2fs 1.42.9 (28-Dec-2013)Filesystem at /dev/VGtest1/LVtest1 is mounted on /appdata; on-line resizing requiredold_desc_blocks = 1, new_desc_blocks = 1The filesystem on /dev/VGtest1/LVtest1 is now 786432 blocks long.xfs系统确认实际使用的命令xfs_growfs /dev/VGtest1/LVtest1查看挂载目录的空间容量大小[root@localhost ~]# df -h|grep VGtest/dev/mapper/VGtest2-LVtest2 976M 2.6M 907M 1% /applog/dev/mapper/VGtest1-LVtest1 3.0G 3.1M 2.8G 1% /appdata数据并没有受损[root@localhost ~]# cat /appdata/test this is a test for LVM
缩减逻辑卷LV
缩减逻辑卷的注意事项：1、查看逻辑卷使用空间状况2、不能在线缩减，得先卸载 切记3、确保缩减后的空间大小依然能存储原有的所有数据4、在缩减之前应该先强行检查文件，以确保文件系统处于一至性状态[root@localhost ~]# e2fsck -f /dev/VGtest1/LVtest1 #处于挂载状态的LV逻辑卷无法强制检查e2fsck 1.42.9 (28-Dec-2013)/dev/VGtest1/LVtest1 is mounted.e2fsck: Cannot continue, aborting.[root@localhost ~]# umount /dev/VGtest1/LVtest1 #取消逻辑卷挂载[root@localhost ~]# e2fsck -f /dev/VGtest1/LVtest1 #检查逻辑卷e2fsck 1.42.9 (28-Dec-2013)Pass 1: Checking inodes, blocks, and sizesPass 2: Checking directory structurePass 3: Checking directory connectivityPass 4: Checking reference countsPass 5: Checking group summary information/dev/VGtest1/LVtest1: 12/196608 files (0.0% non-contiguous), 21309/786432 blocks[root@localhost ~]# resize2fs /dev/VGtest1/LVtest1 1G #首先需要确定缩减逻辑卷到多大空间容量，-1G表示缩减1G大小，1G表示缩减至1G（原来空间是3G）resize2fs 1.42.9 (28-Dec-2013)Resizing the filesystem on /dev/VGtest1/LVtest1 to 262144 (4k) blocks.The filesystem on /dev/VGtest1/LVtest1 is now 262144 blocks long.[root@localhost ~]# lvreduce -L 1G /dev/VGtest1/LVtest1 #再进行逻辑卷LV容量缩减 WARNING: Reducing active logical volume to 1.00 GiB. THIS MAY DESTROY YOUR DATA (filesystem etc.)Do you really want to reduce VGtest1/LVtest1? [y/n]: y Size of logical volume VGtest1/LVtest1 changed from 3.00 GiB (768 extents) to 1.00 GiB (256 extents). Logical volume VGtest1/LVtest1 successfully resized.[root@localhost ~]# mount /dev/VGtest1/LVtest1 /appdata #重新挂载逻辑卷[root@localhost ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 -wi-ao---- 1.00g LVtest2 VGtest2 -wi-ao---- 500.00m root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# df -h|grep VGtest/dev/mapper/VGtest2-LVtest2 460M 1.6M 424M 1% /applog/dev/mapper/VGtest1-LVtest1 976M 2.6M 914M 1% /appdata[root@localhost ~]# cat /appdata/test this is a test for LVM
缩减磁盘空间
发现物理磁盘空间使用不足，将其中一块硬盘或分区拿掉，避免磁盘浪费1、pvmove /dev/sdb1 #将/dev/sdb1上存储的数据移到其它物理卷中2、vgreduce VGtest /dev/sdb1 #将/dev/sdb1从VGtest卷组中移除3、pvremove /dev/sdb1 #将/dev/sdb1从物理卷上移除[root@localhost appdata]# touch stu{0..100}[root@localhost appdata]# pvs PV VG Fmt Attr PSize PFree /dev/sda2 centos lvm2 a-- <19.00g 0 /dev/sdb1 VGtest1 lvm2 a-- <10.00g <9.00g /dev/sdb2 VGtest2 lvm2 a-- <10.00g <9.51g /dev/sdc1 VGtest1 lvm2 a-- <10.00g <10.00g /dev/sdc5 VGtest2 lvm2 a-- <10.00g <10.00g /dev/sdd1 VGtest1 lvm2 a-- <5.00g <5.00g[root@localhost appdata]# pvmove /dev/sdb1 #把sdb1磁盘分区的数据转移到其它磁盘上 /dev/sdb1: Moved: 6.64% /dev/sdb1: Moved: 100.00%[root@localhost appdata]# vgreduce VGtest1 /dev/sdb1 #把分区sdb1从VG卷组中移除 Removed "/dev/sdb1" from volume group "VGtest1"[root@localhost appdata]# pvremove /dev/sdb1 #把sdb1分区从PV物理卷中释放出来 Labels on physical volume "/dev/sdb1" successfully wiped.#如果磁盘划分了多个分区，做成多个物理卷加入了卷组，那么可以能重复以上步骤，把所有的空间都从卷组和物理卷中释放，然后可以拿走这块磁盘做它用实现快照，进行备份还原在/mnt/lvm目录上，我们将原始的目录文件进行快照，然后将/LVtets1目录中的内容清空，并进行还原[root@localhost ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 -wi-ao---- 1.00g LVtest2 VGtest2 -wi-ao---- 500.00m root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# cat /appdata/test this is a test for LVM[root@localhost ~]# df -h|grep VGtest/dev/mapper/VGtest2-LVtest2 460M 1.6M 424M 1% /applog/dev/mapper/VGtest1-LVtest1 976M 2.6M 914M 1% /appdata[root@localhost ~]# lvcreate -L 20M -n appdatabackup -s -p r /dev/VGtest1/LVtest1 #利用LVtest1逻辑卷，快照形成一个备份的物理卷appdatabackup（逻辑卷快照功能） Using default stripesize 64.00 KiB. Logical volume "appdatabackup" created.[root@localhost ~]# lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LVtest1 VGtest1 owi-aos--- 1.00g appdatabackup VGtest1 sri-a-s--- 20.00m LVtest1 0.06 LVtest2 VGtest2 -wi-ao---- 500.00m root centos -wi-ao---- <17.00g swap centos -wi-ao---- 2.00g [root@localhost ~]# mkdir /tmp/backup[root@localhost ~]# mount /dev/VGtest1/appdatabackup /tmp/backup #把快照的逻辑卷挂载到目录上mount: /dev/mapper/VGtest1-appdatabackup is write-protected, mounting read-only[root@localhost ~]# cat /tmp/backup/test this is a test for LVM[root@localhost ~]# ls -l /appdata/test -rw-r--r--. 1 root root 23 Oct 13 12:33 /appdata/test[root@localhost ~]# ls -l /tmp/backup/test -rw-r--r--. 1 root root 23 Oct 13 12:33 /tmp/backup/test[root@localhost ~]# rm -rf /appdata/test #删除LVtest1逻辑卷的数据[root@localhost ~]# ls -l /appdata/test ls: cannot access /appdata/test: No such file or directory[root@localhost ~]# cp /tmp/backup/test /appdata/ #从快照中恢复数据到逻辑卷LVtest1上[root@localhost ~]# ls -l /appdata/test -rw-r--r--. 1 root root 23 Oct 13 13:06 /appdata/test[root@localhost ~]# df -h|grep VGtest/dev/mapper/VGtest2-LVtest2 460M 1.6M 424M 1% /applog/dev/mapper/VGtest1-LVtest1 976M 2.6M 914M 1% /appdata/dev/mapper/VGtest1-appdatabackup 976M 2.6M 914M 1% /tmp/backup 知识扩展
resize2fs命令resize2fs命令被用来增大或者收缩未加载的“ext2/ext3”文件系统的大小。如果文件系统是处于mount状态下，那么它只能做到扩容，前提条件是内核支持在线resize。，linux kernel 2.6支持在mount状态下扩容但仅限于ext3文件系统。-d：打开调试特性；-p：打印已完成的百分比进度条；-f：强制执行调整大小操作，覆盖掉安全检查操作；-F：开始执行调整大小前，刷新文件系统设备的缓冲区如果是xfs文件系统，则需要使用xfs_growfs命令e2fsck命令e2fsck是检查ext2、ext3、ext4等文件系统的正确性。补充说明：e2fsck执行后的传回值及代表意义如下：0 没有任何错误发生。1 文件系统发生错误，并且已经修正。2 文件系统发生错误，并且已经修正。4 文件系统发生错误，但没有修正。8 运作时发生错误。16 使用的语法发生错误。128 共享的函数库发生错误。参 数：-a 不询问使用者意见，便自动修复文件系统。-b <superblock> 指定superblock，而不使用预设的superblock。-B <区块大小> 指定区块的大小，单位为字节。-c 一并执行badblocks，以标示损坏的区块。-C 将检查过程的信息完整记录在file descriptor中，使得整个检查过程都能完整监控。-d 显示排错信息。-f 即使文件系统没有错误迹象，仍强制地检查正确性。-F 执行前先清除设备的缓冲区。-l <文件> 将文件中指定的区块加到损坏区块列表。-L <文件> 先清除损坏区块列表，再将文件中指定的区块加到损坏区块列表。因此损坏区块列表的区块跟文件中指定的区块是一样的。-n 以只读模式开启文件系统，并采取非互动方式执行，所有的问题对话均设置以"no"回答。-p 不询问使用者意见，便自动修复文件系统。-r 此参数只为了兼容性而存在，并无实际作用。-s 如果文件系统的字节顺序不适当，就交换字节顺序，否则不做任何动作。-S 不管文件系统的字节顺序，一律交换字节顺序。-t 显示时间信息。-v 执行时显示详细的信息。-V 显示版本信息。-y 采取非互动方式执行，所有的问题均设置以"yes"回答。转载于:https://blog.51cto.com/13691477/2299707
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