LVM邏輯卷分區大小不固定,可實現動態伸縮,使用更靈活
注意:/boot分區用來存放引導文件,不能基於LVM創建
LVM邏輯卷機制
PV:物理卷,可以是物理分區,也可是整個物理磁盤,有PE組成
VG:卷組,一個或多個PV組成的邏輯整體
LV:從卷組中分割出的一塊邏輯存儲空間,可通過格式化建立文件系統
創建PV,若是分區則要更改文件系統類型爲8e,若是整個磁盤則可直接創建
[root@localhost ~]# fdisk /dev/sdb
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): w
[root@localhost ~]# pvcreate /dev/sdb1 /dev/sdc //pvcreate 設備名
Writing physical volume data to disk "/dev/sdb1"
Physical volume "/dev/sdb1" successfully created
Writing physical volume data to disk "/dev/sdc"
Physical volume "/dev/sdc" successfully created
查看
[root@localhost ~]# pvscan
PV /dev/sdb1 lvm2 [37.26 GB]
PV /dev/sdc lvm2 [80.00 GB]
Total: 2 [117.26 GB] / in use: 0 [0 ] / in no VG: 2 [117.26 GB]
創建卷組
[root@localhost ~]# vgcreate myvg /dev/sdb1 /dev/sdc 可自定義卷組名,如myvg
Volume group "myvg" successfully created
查看
[root@localhost ~]# vgdisplay
創建邏輯卷,-L選項指定邏輯卷大小、-n選項指定邏輯卷名稱,最後一個參數是目標卷組名
[root@localhost ~]# lvcreate -L 20G -n mylv myvg
Logical volume "mylv" created
查看
[root@localhost ~]# lvdisplay
格式化邏輯卷
[root@localhost ~]# mkfs.ext3 /dev/myvg/mylv 也可用“mkfs -t 格式類型 設備名”
掛載
[root@localhost ~]# mount /dev/myvg/mylv /mbox/
驗證
[root@localhost ~]# mount | tail -1
/dev/mapper/myvg-mylv on /mbox type ext3 (rw)
將信息寫入/etc/fstab中,可實現開機自動掛載
測試邏輯卷的數據存取
[root@localhost ~]# echo "Hello World">/mbox/test.txt
[root@localhost ~]# cat /mbox/test.txt
Hello World
邏輯卷支持在線擴展
[root@localhost ~]# lvextend -L +20G /dev/myvg/mylv
Extending logical volume mylv to 40.00 GB
Logical volume mylv successfully resized
此時需要使用resize2fs命令來在線識別新的大小
[root@localhost ~]# resize2fs /dev/myvg/mylv
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/myvg/mylv is mounted on /mbox; on-line resizing required
Performing an on-line resize of /dev/myvg/mylv to 10485760 (4k) blocks.
The filesystem on /dev/myvg/mylv is now 10485760 blocks long.
驗證
[root@localhost ~]# df -h | tail -2
/dev/mapper/myvg-mylv
40G 177M 38G 1% /mbox
注:擴展完成後必須重新識別大小,否則實際的容量不變