一句话总结
本文转自参考文档
LVM:logical volume manager(逻辑卷管理);LVM屏蔽了底层磁盘布局,方便于动态调整磁盘容量。
创建逻辑卷的步骤
1)通过fdisk 工具将磁盘转换为linux分区;
2)通过pvcreate命令将linux分区转换成物理卷(PV);
3)通过vgcreate命令将创建好的物理卷处理成卷组(VG);
4)通过lvcreate命令将卷组分成若干个逻辑卷(LV);
5)对逻辑卷进行格式化,挂载,动态调整逻辑卷的大小,并且该操作不会影响逻辑卷(Lv)上的数据。
物理卷(PV)创建及管理具体操作步骤
1.先查看linux分区,将未使用空间转换为物理卷(先使用fdisk建立普通分区)
[root@RHEL5 ~]# fdisk -l /dev/sdb #查看linux分区情况
Disk /dev/sdb: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sdb1 1 500 4016218+ 83 Linux
/dev/sdb2 5011000 4016250 83 Linux
/dev/sdb310011500 4016250 83 Linux
/dev/sdb415012610 89160755 Extended
/dev/sdb515012610 8916043+ 83 Linux
备注:/dev/sdb是一块新增加的磁盘,上面没有任何数据,也未挂载
2.将linux物理分区转变为物理卷
[root@RHEL5 ~]# pvcreate /dev/sdb{1,2} #将物理分区/dev/sdb{1,2}转变为物理卷
Physical volume "/dev/sdb1" successfully created
Physical volume "/dev/sdb2" successfully created
3.使用Pvscan查看物理卷信息
[root@RHEL5 ~]# pvscan #查看物理卷信息,会显示所有物理卷信息
PV /dev/sda2 VG VolGroup00 lvm2 [39.88 GB / 0free]
PV /dev/sdb1 lvm2 [3.83 GB]
PV /dev/sdb2 lvm2 [3.83 GB]
Total: 3 [47.54 GB] / in use: 1 [39.88 GB] / in no VG: 2 [7.66 GB]
4.使用pvdisplay查看各物理卷详细参数
[root@RHEL5 ~]# pvdisplay #查看各物理卷详细参数
--- Physical volume ---
PV Name /dev/sda2
VG Name VolGroup00
PV Size 39.90 GB / not usable 20.79 MB
Allocatable yes (but full)
PE Size (KByte) 32768
Total PE 1276
Free PE 0
Allocated PE 1276
PV UUID aJlaad-NHPT-Cgg3-7yu4-a2RJ-kJJ1-qxSFgD
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 3.83 GB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID v2VajD-yS53-SiQA-yTzu-KOiD-RyT3-p0wTvt
--- NEW Physical volume ---
PV Name /dev/sdb2
VG Name
PV Size 3.83 GB
Allocatable NO
PE Size (KByte) 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID iOoK3V-yuww-ZlLF-cRLq-v7hC-CL7c-0bQU1x
当物理卷没有被使用时可删除物理卷
[root@RHEL5 /]# pvremove /dev/sdb2 #删除物理卷,
Labels on physical volume "/dev/sdb2" successfully wiped
卷组(VG)创建及管理具体操作步骤
1.使用vgcreate将物理卷转化为卷组
[root@RHEL5 /]# vgcreate vg01 /dev/sdb{1,2} #将已经是物理卷的/dev/sdb{1,2}转化为卷组名为vg01的卷组
Volume group "vg01" successfully created
备注:以上未加参数,扩展块(PE)大小默认4M,若通过 vgcreate -s 8M vg01 /dev/sdb{1,2},则指定了扩展块大小为8M
2.使用vgdisplay 查看所有卷组详细信息
[root@RHEL5 /]# vgdisplay #看所有卷组详细信息
--- Volume group ---
VG Name vg01
System ID
Formatlvm2
Metadata Areas2
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV0
Cur LV0
Open LV 0
Max PV0
Cur PV2
Act PV2
VG Size 7.66 GB
PE Size 4.00 MB
Total PE 1960
Alloc PE / Size 0 / 0
Free PE / Size 1960 / 7.66 GB
VG UUID 1g8QL0-0cGM-TJji-Q98P-LJ3f-PhDN-2ouSM3
--- Volume group ---
VG Name VolGroup00
System ID
Formatlvm2
Metadata Areas1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV0
Cur LV2
Open LV 2
Max PV0
Cur PV1
Act PV1
VG Size 39.88 GB
PE Size 32.00 MB
Total PE 1276
Alloc PE / Size 1276 / 39.88 GB
Free PE / Size 0 / 0
VG UUID AhhisY-vDrc-s4jx-XIsn-QmCp-wMiT-2v01YZ
备注:也可以查看具体某一卷组详细信息
[root@RHEL5 /]# vgdisplay -v /dev/vg01
3.查看卷组信息
[root@RHEL5 /]# vgscan#查看卷组信息
Reading all physical volumes. This may take a while...
Found volume group "vg01" using metadata type lvm2
Found volume group "VolGroup00" using metadata type lvm2
4.扩展卷组vgextend,将某个物理卷添加到已存在的卷组中
[root@RHEL5 /]# pvcreate /dev/sdb3 #创建一个新的物理卷
Physical volume "/dev/sdb3" successfully created
[root@RHEL5 /]# vgextend vg01 /dev/sdb3 #将新增的物理卷添加到vg01卷组中
Volume group "vg01" successfully extended
使用vgremove删除卷组
[root@RHEL5 /]# vgremove /dev/vg01
Volume group "vg01" successfully removed
逻辑卷(LV)创建及管理具体操作步骤
1.创建逻辑卷大小为6G卷名为data,从vg01生成
[root@RHEL5 /]# lvcreate -L 6G -n data vg01 #从卷组vg01上划分6G的空间为逻辑卷data
Logical volume "data" created
2.对划分的逻辑卷进行格式化
[root@RHEL5 /]# mkfs -t ext3 /dev/vg01/data #以ext3的文件格式化逻辑卷
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
786432 inodes, 1572864 blocks
78643 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1610612736
48 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 35 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override
备注:也可通过下面命令格式化
[root@RHEL5 /]# mkfs.ext3 /dev/vg01/data
3.使用lvsacn查看逻辑卷的信息
[root@RHEL5 /]# lvscan#查看逻辑卷的信息
ACTIVE'/dev/vg01/data' [6.00 GB] inherit
ACTIVE'/dev/VolGroup00/LogVol00' [38.88 GB] inherit
ACTIVE'/dev/VolGroup00/LogVol01' [1.00 GB] inherit
4.使用lvdisplay查看逻辑卷的具体参数
[root@RHEL5 /]# lvdisplay #查看逻辑卷的具体参数
--- Logical volume ---
LV Name/dev/vg01/data
VG Namevg01
LV UUIDQUmuTB-ofgI-9BbG-1DvN-gWzo-7Vqb-Twmf45
LV Write Accessread/write
LV Status available
# open 0
LV Size6.00 GB
Current LE 1536
Segments 2
Allocation inherit
Read ahead sectors 0
Block device 253:2
--- Logical volume ---
LV Name/dev/VolGroup00/LogVol00
VG NameVolGroup00
LV UUIDSrNP2L-bOWm-4clq-22Lh-Fg10-ydeg-7dNpdH
LV Write Accessread/write
LV Status available
# open 1
LV Size38.88 GB
Current LE 1244
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:0
--- Logical volume ---
LV Name/dev/VolGroup00/LogVol01
VG NameVolGroup00
LV UUIDe7u6Wx-MXhq-Nc2o-lrF9-yea1-Hia5-Cv7d7e
LV Write Accessread/write
LV Status available
# open 1
LV Size1.00 GB
Current LE 32
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:1
备注:也查看某一逻辑卷详细参数
[root@RHEL5 /]# lvdisplay -v /dev/vg01/data
5.使用lvextend增大逻辑卷大小,在线扩容
[root@RHEL5 /]# lvextend -L +1G /dev/vg01/data #从卷组vg01上对逻辑卷/dev/vg01/data进行扩容,逻辑卷大小变为7GB
Extending logical volume data to 7.00 GB
Logical volume data successfully resized
6.使用resize2fs命令更新系统识别的文件系统大小,立即生效
oot@RHEL5 /]# resize2fs /dev/vg01/data #使增加的逻辑卷大小立即生效 resize2fs 1.39 (29-May-2006) Resizing the filesystem on /dev/vg01/data to 1835008 (4k) blocks. The filesystem on /dev/vg01/data is now 1835008 blocks long.
7.使用lvreduce减小逻辑卷大小,必须是离线方式(即先卸载文件系统)
[root@RHEL5 /]# lvreduce -L -1G /dev/vg01/data #将逻辑卷/dev/vg01/data容量减小1GB
/dev/cdrom: open failed: Read-only file system
WARNING: Reducing active logical volume to 6.00 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce data? [y/n]: y
Reducing logical volume data to 6.00 GB
Logical volume data successfully resized
[root@RHEL5 /]# resize2fs /dev/vg01/data#使减少的逻辑卷大小立即生效
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vg01/data to 1572864 (4k) blocks.
resize2fs: Can't read an block bitmap while trying to resize /dev/vg01/data
备注:缩小逻辑卷通常要先卸载文件系统,并且缩小后空间容量必须大于等于文件当前占用的容量,若操作不当,会导致数据丢失,须谨慎。
[root@RHEL5 /]# lvscan #查看逻辑卷大小变为6GB
ACTIVE'/dev/vg01/data' [6.00 GB] inherit
ACTIVE'/dev/VolGroup00/LogVol00' [38.88 GB] inherit
ACTIVE'/dev/VolGroup00/LogVol01' [1.00 GB] inherit