lvscan 查看系统中存在的所有LVM逻辑卷
lvscan指令：扫描逻辑卷
【语 法】lvscan [选项]
【功能介绍】lvscan指令用于扫描当前系统中存在的所有的LVM逻辑卷。
主要参数
-b 显示逻辑卷的主设备号和次设备号
例1
磁盘信息
[root@localhost /]# fdisk -l
磁盘 /dev/sda：214.7 GB, 214748364800 字节，419430400 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节
磁盘标签类型：dos
磁盘标识符：0x000bd010
设备 Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 419430399 209202176 8e Linux LVM
磁盘 /dev/mapper/centos-root：205.6 GB, 205621559296 字节，401604608 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节
磁盘 /dev/mapper/centos-swap：8594 MB, 8594128896 字节，16785408 个扇区
Units = 扇区 of 1 * 512 = 512 bytes
扇区大小(逻辑/物理)：512 字节 / 512 字节
I/O 大小(最小/最佳)：512 字节 / 512 字节
[root@localhost /]#
LV阶段，逻辑卷操作
[root@www ~]# pvscan #有三个 PV 被用去，剩下一个 /dev/hda9 的 PV 沒被用掉！
PV /dev/hda6 VG vbirdvg lvm2 [1.39 GB / 1.39 GB free]
PV /dev/hda7 VG vbirdvg lvm2 [1.39 GB / 1.39 GB free]
PV /dev/hda8 VG vbirdvg lvm2 [1.39 GB / 1.39 GB free]
PV /dev/hda9 lvm2 [1.40 GB]
Total: 4 [5.57 GB] / in use: 3 [4.17 GB] / in no VG: 1 [1.40 GB]
[root@www ~]# vgdisplay # 最后那三行指的就是 PE 能够使用的情況！由于尚未切出 LV，因此所有的 PE均可自由使用。
--- Volume group ---
VG Name vbirdvg
System ID
Format lvm2
Metadata Areas 3
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 3
Act PV 3
VG Size 4.17 GB #整个 VG 容量就这么大
PE Size 16.00 MB #內部每个 PE 的大小
Total PE 267 #总共的 PE 数量！
Alloc PE / Size 0 / 0
Free PE / Size 267 / 4.17 GB
VG UUID 4VU5Jr-gwOq-jkga-sUPx-vWPu-PmYm-dZH9EO
[root@www ~]# lvcreate -l 356 -n vbirdlv vbirdvg #将整个 vbirdvg 通通分配給 vbirdlv 啊，要注意， PE 共有 356 个
Logical volume "vbirdlv" created
[root@www ~]# ll /dev/vbirdvg/vbirdlv
lrwxrwxrwx 1 root root 27 Mar 11 16:49 /dev/vbirdvg/vbirdlv -> /dev/mapper/vbirdvg-vbirdlv # 看见了沒有啊！这就是我们最重要的一步
[root@www ~]# lvdisplay
--- Logical volume ---
LV Name /dev/vbirdvg/vbirdlv #LV逻辑卷的名字
VG Name vbirdvg
LV UUID 8vFOPG-Jrw0-Runh-ug24-t2j7-i3nA-rPEyq0
LV Write Access read/write
LV Status available
# open 0
LV Size 5.56 GB #LV的大小
Current LE 356
Segments 4
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
格式化逻辑卷，并且挂载
[root@www ~]# mkfs -t ext3 /dev/vbirdvg/vbirdlv #格式化
[root@www ~]# mkdir /mnt/lvm
[root@www ~]# mount /dev/vbirdvg/vbirdlv /mnt/lvm #挂载目录
[root@www ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda2 9920624 3858984 5549572 42% /
/dev/hda3 4956316 1056996 3643488 23% /home
/dev/hda1 101086 21408 74459 23% /boot
tmpfs 371332 0 371332 0% /dev/shm
/dev/mapper/vbirdvg-vbirdlv
5741020 142592 5306796 3% /mnt/lvm
增加 LV 容量
[root@www ~]# fdisk -l
Device Boot Start End Blocks Id System
....(中间省略)....
/dev/hda10 2785 3150 2939863+ 8e Linux LVM #增加一下lvm /dev/hda10
[root@www ~]# pvcreate /dev/hda10 建立新的 PV
Physical volume "/dev/hda10" successfully created
[root@www ~]# pvscan #查看PG物理卷
PV /dev/hda6 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda7 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda8 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda9 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda10 lvm2 [2.80 GB] # 可以看到 /dev/hda10 是新加入，尚未使用
Total: 5 [8.37 GB] / in use: 4 [5.56 GB] / in no VG: 1 [2.80 GB]
[root@www ~]# vgextend vbirdvg /dev/hda10 #加大 VG ，利用 vgextend 功能
Volume group "vbirdvg" successfully extended
[root@www ~]# vgdisplay #查看VG逻辑卷组
--- Volume group ---
VG Name vbirdvg
System ID
Format lvm2
Metadata Areas 5
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 5
Act PV 5
VG Size 8.36 GB
PE Size 16.00 MB
Total PE 535
Alloc PE / Size 356 / 5.56 GB
Free PE / Size 179 / 2.80 GB
VG UUID 4VU5Jr-gwOq-jkga-sUPx-vWPu-PmYm-dZH9EO
[root@www ~]# lvresize -l +179 /dev/vbirdvg/vbirdlv #利用 lvresize 的功能來增加LV
Extending logical volume vbirdlv to 8.36 GB
Logical volume vbirdlv successfully resized
[root@www ~]# lvdisplay #显示LV逻辑卷
--- Logical volume ---
LV Name /dev/vbirdvg/vbirdlv
VG Name vbirdvg
LV UUID 8vFOPG-Jrw0-Runh-ug24-t2j7-i3nA-rPEyq0
LV Write Access read/write
LV Status available
# open 1
LV Size 8.36 GB
Current LE 535
Segments 5
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
[root@www ~]# df /mnt/lvm #查看大小
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vbirdvg-vbirdlv
5741020 261212 5188176 5% /mnt/lvm
[root@www ~]# resize2fs /dev/vbirdvg/vbirdlv #LV分区重设大小
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/vbirdvg/vbirdlv is mounted on /mnt/lvm; on-line resizing
Performing an on-line resize of /dev/vbirdvg/vbirdlv to 2191360 (4k) blocks.
The filesystem on /dev/vbirdvg/vbirdlv is now 2191360 blocks long.
减小 LV 容量
[root@www ~]# umount /mnt/lvm #取消挂载
[root@www ~]# e2fsck -f /dev/vbirdvg/vbirdlv #磁盘检测
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vbirdvg/vbirdlv: 2438/1087008 files (0.1% non-contiguous),
[root@www ~]# resize2fs /dev/vbirdvg/vbirdlv 6900M #重设大小
resize2fs 1.39 (29-May-2006)
Resizing the filesystem on /dev/vbirdvg/vbirdlv to 1766400 (4k) blocks.
The filesystem on /dev/vbirdvg/vbirdlv is now 1766400 blocks long.
[root@www ~]# mount /dev/vbirdvg/vbirdlv /mnt/lvm #挂载LVM
[root@www ~]# df /mnt/lvm
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vbirdvg-vbirdlv
6955584 262632 6410328 4% /mnt/lvm
[root@www ~]# lvresize -l -89 /dev/vbirdvg/vbirdlv #降低 LV 的容量
WARNING: Reducing active and open logical volume to 6.97 GB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vbirdlv? [y/n]: y
Reducing logical volume vbirdlv to 6.97 GB
Logical volume vbirdlv successfully resized
[root@www ~]# lvdisplay #查看lv逻辑卷信息
--- Logical volume ---
LV Name /dev/vbirdvg/vbirdlv
VG Name vbirdvg
LV UUID 8vFOPG-Jrw0-Runh-ug24-t2j7-i3nA-rPEyq0
LV Write Access read/write
LV Status available
# open 1
LV Size 6.97 GB
Current LE 446
Segments 5
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
[root@www ~]# pvdisplay #先确认 /dev/hda6 是否將 PE 都移除了
--- Physical volume ---
PV Name /dev/hda6
VG Name vbirdvg
PV Size 1.40 GB / not usable 11.46 MB
Allocatable yes (but full)
PE Size (KByte) 16384
Total PE 89
Free PE 0
Allocated PE 89
PV UUID Z13Jk5-RCls-UJ8B-HzDa-Gesn-atku-rf2biN
....(中間省略)....
--- Physical volume ---
PV Name /dev/hda10
VG Name vbirdvg
PV Size 2.80 GB / not usable 6.96 MB
Allocatable yes
PE Size (KByte) 16384
Total PE 179
Free PE 89
Allocated PE 90
PV UUID 7MfcG7-y9or-0Jmb-H7RO-5Pa5-D3qB-G426Vq
[root@www ~]# pvmove /dev/hda6 /dev/hda10 #將 /dev/hda6 內的 PE 移动到 /dev/hda10
[root@www ~]# vgreduce vbirdvg /dev/hda6 #將 /dev/hda6从vbirdvg 移出
Removed "/dev/hda6" from volume group "vbirdvg"
[root@www ~]# pvscan
PV /dev/hda7 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda8 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda9 VG vbirdvg lvm2 [1.39 GB / 0 free]
PV /dev/hda10 VG vbirdvg lvm2 [2.80 GB / 0 free]
PV /dev/hda6 lvm2 [1.40 GB]
Total: 5 [8.37 GB] / in use: 4 [6.97 GB] / in no VG: 1 [1.40 GB]
[root@www ~]# pvremove /dev/hda6 #移出物理卷hda6
Labels on physical volume "/dev/hda6" successfully wiped
快照区的建立
[root@www ~]# vgdisplay #查看VG容量
--- Volume group ---
VG Name vbirdvg
....(其他省略)....
VG Size 6.97 GB
PE Size 16.00 MB
Total PE 446
Alloc PE / Size 446 / 6.97 GB
Free PE / Size 0 / 0
[root@www ~]# pvcreate /dev/hda6 #创建PV物理卷
Physical volume "/dev/hda6" successfully created
[root@www ~]# vgextend vbirdvg /dev/hda6 #将刚刚移除的 /dev/hda6 加入這個 VG
Volume group "vbirdvg" successfully extended
[root@www ~]# vgdisplay #查看VG
--- Volume group ---
VG Name vbirdvg
....(其他省略)....
VG Size 8.36 GB
PE Size 16.00 MB
Total PE 535
Alloc PE / Size 446 / 6.97 GB
Free PE / Size 89 / 1.39 GB #多出了 89 个 可用PE
[root@www ~]# lvcreate -l 60 -s -n vbirdss /dev/vbirdvg/vbirdlv #利用 lvcreate 建立系统快照区，命名为vbirdss，且经于 60 个 PE
Logical volume "vbirdss" created
[root@www ~]# lvdisplay
--- Logical volume ---
LV Name /dev/vbirdvg/vbirdss
VG Name vbirdvg
LV UUID K2tJ5E-e9mI-89Gw-hKFd-4tRU-tRKF-oeB03a
LV Write Access read/write
LV snapshot status active destination for /dev/vbirdvg/vbirdlv
LV Status available
# open 0
LV Size 6.97 GB #原LV的大小
Current LE 446
COW-table size 960.00 MB #新建快照区的实际大小
COW-table LE 60 #快照区占有的PE
Allocated to snapshot 0.00%
Snapshot chunk size 4.00 KB
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:1
[root@www ~]# mkdir /mnt/snapshot
[root@www ~]# mount /dev/vbirdvg/vbirdss /mnt/snapshot
[root@www ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/hda2 9920624 3859032 5549524 42% /
/dev/hda3 4956316 1056996 3643488 23% /home
/dev/hda1 101086 21408 74459 23% /boot
tmpfs 371332 0 371332 0% /dev/shm
/dev/mapper/vbirdvg-vbirdlv
6955584 262632 6410328 4% /mnt/lvm #二个一样
/dev/mapper/vbirdvg-vbirdss
6955584 262632 6410328 4% /mnt/snapshot #二个一样
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