個人理解: 我們可以通過lvcreate在VG中劃分出某個區域.然後通過mount到某個文件夾中,這樣,偶們就可以使用這個區域了.注意哦,是在這個卷組中劃出一塊地出來使用,當然了,如果這塊的太少了,我們可以很輕松的把別人的地挪到自己這來.地裡面的莊稼當然不會少了.如果覺得地太多了,割出部分出去,莊稼會自動騰到沒割的地方去.這就是LVM的好處了.
OK,下面來看下我的操作過程了,其它的概念大家可以去看下別人寫的文章.很詳細的.
假設我有一塊空閒硬盤,硬盤符是/dev/sdb,在裡面分了三個分區,分別是 /dev/sdb1 /dev/sdb2 /dev/sdb3 三個都分別是100M.看下
[root@localhost /]# fdisk /dev/sdb
Command (m for help): p
Disk /dev/sdb: 2147 MB, 2147483648 bytes 255 heads, 63 sectors/track, 261 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System /dev/sdb1 1 13 104391 8e Linux LVM #看到Id是8e哦. /dev/sdb2 14 26 104422+ 8e Linux LVM /dev/sdb3 27 39 104422+ 8e Linux LVM
好得,下一步,建立物理卷PV
[root@localhost /]# pvcreate /dev/sdb1 /dev/sdb2 /dev/sdb3 Physical volume "/dev/sdb1" successfully created Physical volume "/dev/sdb2" successfully created Physical volume "/dev/sdb3" successfully created
創建VG卷組
[root@localhost /]# vgscan #一般我們初始建立卷組時都要先scan下. Reading all physical volumes. This may take a while... Couldn't find device with uuid '6T3gUb-fFdj-MMUL-wUTN-qdXG-8iEP-KsWbgb'. Couldn't find all physical volumes for volume group VolGroup00. Couldn't find device with uuid '6T3gUb-fFdj-MMUL-wUTN-qdXG-8iEP-KsWbgb'. Couldn't find all physical volumes for volume group VolGroup00. Volume group "VolGroup00" not found [root@localhost /]# vgcreate vg0 /dev/sdb1 /dev/sdb2 #建立卷組,名字叫:vg0 Volume group "vg0" successfully created [root@localhost /]# [root@localhost /]# vgdisplay vg0 # 查看下卷組vg0得情況 --- Volume group --- VG Name vg0 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 200.00 MB PE Size 4.00 MB #默認PE 都是4M, 通過 vgcreate -s 8M 可修改. Total PE 50 Alloc PE / Size 0 / 0 Free PE / Size 50 / 200.00 MB VG UUID WKRPJT-MI6G-vGk9-vne2-Gfg2-sAry-llsF7B 請輸入內容
OK,下面是建立邏輯卷了,在這不我添加了名字為data 的邏輯卷了. 注意:-L 和-l的區別,前面是根據大小來的,後面的是根據塊數來的,也就是幾個PE.
[root@localhost /]# lvcreate -n data -L 10M vg0 #建立名為data,大小10M /dev/cdrom: open failed: Read-only file system Rounding up size to full physical extent 12.00 MB Logical volume "data" created [root@localhost /]# lvdisplay #查看下邏輯卷情況 --- Logical volume --- LV Name /dev/vg0/data VG Name vg0 LV UUID qrC9H4-iHWi-Si4m-hN7G-x6Cm-yupr-aXRBVi LV Write Access read/write LV Status available # open 0 LV Size 12.00 MB #為什麼是12M呢?我不是輸入10M大小的嗎? Current LE 3 就當是個問題考考大家了, Segments 1 Allocation inherit Read ahead sectors 0 Block device 253:2
Couldn't find device with uuid '6T3gUb-fFdj-MMUL-wUTN-qdXG-8iEP-KsWbgb'. Couldn't find all physical volumes for volume group VolGroup00. Couldn't find device with uuid '6T3gUb-fFdj-MMUL-wUTN-qdXG-8iEP-KsWbgb'. Couldn't find all physical volumes for volume group VolGroup00. Volume group "VolGroup00" not found [root@localhost /]# mkfs.ext3 /dev/vg0/data #格式化成ext3格式. mke2fs 1.35 (28-Feb-2004) Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) 3072 inodes, 12288 blocks 614 blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks=12582912 2 block groups 8192 blocks per group, 8192 fragments per group 1536 inodes per group Superblock backups stored on blocks: 8193
Writing inode tables: done Creating journal (1024 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. [root@localhost /]# mount /dev/vg0/data /mnt/ #mount到/mnt文件夾 [root@localhost /]# cp /etc/services /mnt/ #拷貝個文件進去試下 [root@localhost /]# ls /mnt/ #看下,裡面已經有個services文件了.成功. lost+found services [root@localhost /]# umount /mnt/ [root@localhost /]# lvextend -L +10M /dev/vg0/data #擴展邏輯卷大小 /dev/cdrom: open failed: Read-only file system Rounding up size to full physical extent 12.00 MB Extending logical volume data to 24.00 MB Logical volume data successfully resized
OK,試驗就做到這了,是不是很容易啊,其它比如物理卷擴展大小,刪除等操作其實已經大同小異了.
