LVM應用實例
案例的環境和需求描述如下：公司準備在Internet中搭建郵件服務器（RHEL 6系統平臺），面向全國各地的員工及部分VIP客戶提供電子郵箱空間。由於用戶數量衆多，郵件存儲需要大量的空間，考慮到動態擴容的需要，計劃增加兩塊SCSI硬盤並構建LVM邏輯卷 (掛載到“/mailbox”目錄下）專門用於存放郵件數據。
根據上述案例環境和需求，推薦的操作步驟如下所述。
(1 )關閉服務器主機，打開機箱，正確掛接兩塊SCSI新硬盤。
(2 )開啓服務器主機，並執行“fdisk -I”命令進行檢查，確認已識別新增的硬盤（sdb、 sdc )。
(3)在新磁盤中進行分區，將每塊硬盤的所有空間劃分爲一個獨立的主分區，並將分區類型更改爲“8e”分好區後使用“fdisk- l”命令查看，確認結果如下所示。
一、格式化、轉換分區類型
1.把sdb2轉換成LVM類型的分區：
[root@test2 /]# fdisk /dev/sdb
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): t
Partition number (1-4): 2
Hex code (type L to list codes): 8e
Changed system type of partition 2 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdb: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa8f24694
Device Boot Start End Blocks Id System
/dev/sdb1 1 2612 20980858+ 83 Linux
/dev/sdb2 2613 5224 20980890 8e Linux LVM
/dev/sdb3 5225 10443 41921617+ 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@test2 /]#
2.創建sdc2分區，並轉變成LVM類型：
[root@test2 /]# fdisk /dev/sdc
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
2
Invalid partition number for type `2'
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (2613-10443, default 2613):
Using default value 2613
Last cylinder, +cylinders or +size{K,M,G} (2613-10443, default 10443): +20F
Unsupported suffix: 'F'.
Supported: 10^N: KB (KiloByte), MB (MegaByte), GB (GigaByte)
2^N: K (KibiByte), M (MebiByte), G (GibiByte)
Last cylinder, +cylinders or +size{K,M,G} (2613-10443, default 10443): +20G
Command (m for help): P
Disk /dev/sdc: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8967e34e
Device Boot Start End Blocks Id System
/dev/sdc1 1 2612 20980858+ 83 Linux
/dev/sdc2 2613 5224 20980890 83 Linux
錯誤操作：
Command (m for help): T
Partition number (1-4): be
Partition number (1-4): 2
Hex code (type L to list codes): b
Changed system type of partition 2 to b (W95 FAT32)
正確操作：
Command (m for help): t
Partition number (1-4): 2
Hex code (type L to list codes): 8e
Changed system type of partition 2 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdc: 85.9 GB, 85899345920 bytes
255 heads, 63 sectors/track, 10443 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8967e34e
Device Boot Start End Blocks Id System
/dev/sdc1 1 2612 20980858+ 83 Linux
/dev/sdc2 2613 5224 20980890 8e Linux LVM
Command (m for help):
3.保存
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
The kernel still uses the old table. The new table will be used at
the next reboot or after you run partprobe(8) or kpartx(8)
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
information.
Syncing disks.
4.探測
探測失敗
[root@test2 /]# partx /dev/sdc
sdc sdc1
[root@test2 /]# partx /dev/sdc
sdc sdc1
[root@test2 /]# partx -a /dev/sdc
sdc sdc1
[root@test2 /]# partx -a /dev/sdc
sdc sdc1
重啓：
識別成功：
[root@test2 jason]# partprobe /dev/sdc
sdc sdc1 sdc2
[root@test2 jason]# partprobe /dev/sdc
當前pv的信息
[root@test2 jason]# pvscan
PV /dev/sda2 VG vg_jason lvm2 [19.51 GiB / 0 free]
PV /dev/sdb1 lvm2 [20.01 GiB]
PV /dev/sdb2 lvm2 [20.01 GiB]
Total: 3 [59.53 GiB] / in use: 1 [19.51 GiB] / in no VG: 2 [40.02 GiB]
[root@test2 jason]#
二、創建Logical Volume
1.創建pv
將sdc2創建成physical volume(物理卷）：
[root@test2 jason]# pvcreate /dev/sdc2
Physical volume "/dev/sdc2" successfully created
[root@test2 jason]#
再次查看pv信息：
[root@test2 jason]# pvscan
PV /dev/sda2 VG vg_jason lvm2 [19.51 GiB / 0 free]
PV /dev/sdb1 lvm2 [20.01 GiB]
PV /dev/sdb2 lvm2 [20.01 GiB]
PV /dev/sdc2 lvm2 [20.01 GiB]
Total: 4 [79.53 GiB] / in use: 1 [19.51 GiB] / in no VG: 3 [60.03 GiB]
[root@test2 jason]#
2.創建 VG
vg的信息：
[root@test2 jason]# lvscan
ACTIVE '/dev/vg_jason/lv_root' [17.51 GiB] inherit
ACTIVE '/dev/vg_jason/lv_swap' [2.00 GiB] inherit
創建mail_store的volume group（卷組）：
[root@test2 jason]# pvcreate mail_store /dev/sdb2 /dev/sdc2
Device mail_store not found (or ignored by filtering).
dev_is_mpath: failed to get device for 8:18
Physical volume "/dev/sdb2" successfully created
Physical volume "/dev/sdc2" successfully created
[root@test2 jason]#
再次查看vg信息：
[root@test2 jason]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "vg_jason" using metadata type lvm2
分析是因爲上面的命令用錯了，應該是vgcreate，而不是pvcreate
重新創建並查看：
[root@test2 jason]# vgcreate mail_store /dev/sdb2 /dev/sdc2
Volume group "mail_store" successfully created
[root@test2 jason]# vgscan
Reading all physical volumes. This may take a while...
Found volume group "mail_store" using metadata type lvm2
Found volume group "vg_jason" using metadata type lvm2
[root@test2 jason]#
mail_store成功創建，並能通過vgscan查找到
[root@test2 jason]# lvcreate -L 35G -n mbox mail_store
Logical volume "mbox" created
[root@test2 jason]# lvscan
ACTIVE '/dev/mail_store/mbox' [35.00 GiB] inherit
ACTIVE '/dev/vg_jason/lv_root' [17.51 GiB] inherit
ACTIVE '/dev/vg_jason/lv_swap' [2.00 GiB] inherit
[root@test2 jason]#
3.創建LV
創建前的lvscan：
[root@test2 jason]# lvscan
ACTIVE '/dev/vg_jason/lv_root' [17.51 GiB] inherit
ACTIVE '/dev/vg_jason/lv_swap' [2.00 GiB] inherit
創建mbox的lv並查看：
[root@test2 jason]# lvcreate -L 35G -n mbox mail_store
Logical volume "mbox" created
[root@test2 jason]# lvscan
ACTIVE '/dev/mail_store/mbox' [35.00 GiB] inherit
ACTIVE '/dev/vg_jason/lv_root' [17.51 GiB] inherit
ACTIVE '/dev/vg_jason/lv_swap' [2.00 GiB] inherit
[root@test2 jason]#
創建目錄
[root@test2 /]# mkdir /mailbox
4.格式化：
格式化成ext4
[root@test2 /]# mkfs.ext4 /dev/mail_store/mbox
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
2293760 inodes, 9175040 blocks
458752 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
280 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 30 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@test2 /]#
5.掛載並查看：
[root@test2 /]# mount /dev/mail_store/mbox /mailbox/
[root@test2 /]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 421M 19G 3% /home
/dev/mapper/mail_store-mbox ext4 35G 176M 33G 1% /mailbox
[root@test2 /]#
三、拓展篇：
1.在虛擬機中新建一個100G的硬盤（略）：
2.只建一個分區，並轉換成爲LVM類型：
[root@test2 jason]# fdisk /dev/sdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xef9a8da9.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-13054, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-13054, default 13054):
Using default value 13054
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): p
Disk /dev/sdd: 107.4 GB, 107374182400 bytes
255 heads, 63 sectors/track, 13054 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xef9a8da9
Device Boot Start End Blocks Id System
/dev/sdd1 1 13054 104856223+ 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@test2 jason]#
探測：
[root@test2 jason]# partprobe /dev/sdd
sdd sdd1
[root@test2 jason]# partprobe /dev/sdd
3.創建pv：
[root@test2 jason]# pvcreate /dev/sdd1
dev_is_mpath: failed to get device for 8:49
Physical volume "/dev/sdd1" successfully created
vg拓展mail_store：
[root@test2 jason]# vgextend mail_store /dev/sdd1
Volume group "mail_store" successfully extended
vgdisplay mail_store：
[root@test2 jason]# vgdisplay mail_store
--- Volume group ---
VG Name mail_store
System ID
Format lvm2
Metadata Areas 3
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 3
Act PV 3
VG Size 140.01 GiB
PE Size 4.00 MiB
Total PE 35843
Alloc PE / Size 8960 / 35.00 GiB
Free PE / Size 26883 / 105.01 GiB
VG UUID yHpVfR-lbFL-vs9A-mzgz-m800-JLE2-Dt2z6F
[root@test2 jason]#
4.LV擴容
錯誤的語法：
[root@test2 jason]# lvextend -L +85G mbox mail_store
Path required for Logical Volume "mbox"
Please provide a volume group name
Run `lvextend --help' for more information.
正確的lv擴容操作：
[root@test2 jason]# lvextend -L +85G /dev/mail_store/mbox
Extending logical volume mbox to 120.00 GiB
Logical volume mbox successfully resized
擴容後查看：
[root@test2 jason]# lvscan
ACTIVE '/dev/mail_store/mbox' [120.00 GiB] inherit
ACTIVE '/dev/vg_jason/lv_root' [17.51 GiB] inherit
ACTIVE '/dev/vg_jason/lv_swap' [2.00 GiB] inherit
5.掛載
剛纔爲了重新加一個100G的硬盤重啓，重啓後的mount信息：
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 421M 19G 3% /home
[root@test2 jason]# mount
/dev/mapper/vg_jason-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/sdc1 on /home type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock (rw,nosuid,nodev,default_permissions,allow_other)
重新掛載並查看：
[root@test2 jason]# mount /dev/mail_store/mbox /mailbox/
[root@test2 jason]# mount
/dev/mapper/vg_jason-lv_root on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
/dev/sdc1 on /home type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
vmware-vmblock on /var/run/vmblock-fuse type fuse.vmware-vmblock (rw,nosuid,nodev,default_permissions,allow_other)
/dev/mapper/mail_store-mbox on /mailbox type ext4 (rw)
查看mbox的容量：
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 421M 19G 3% /home
/dev/mapper/mail_store-mbox ext4 35G 176M 33G 1% /mailbox
6.更新磁盤容量
查看resize2fs的用法：
[root@test2 jason]# resize2fs
resize2fs 1.41.12 (17-May-2010)
Usage: resize2fs [-d debug_flags] [-f] [-F] [-M] [-P] [-p] device [new_size]
使用resize2fs更新mbox的容量：
[root@test2 jason]# resize2fs /dev/mail_store/mbox
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mail_store/mbox is mounted on /mailbox; on-line resizing required
old desc_blocks = 3, new_desc_blocks = 8
Performing an on-line resize of /dev/mail_store/mbox to 31457280 (4k) blocks.
The filesystem on /dev/mail_store/mbox is now 31457280 blocks long.
更新成功：
[root@test2 jason]# df -hT
Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/vg_jason-lv_root ext4 18G 4.3G 13G 27% /
tmpfs tmpfs 3.9G 72K 3.9G 1% /dev/shm
/dev/sda1 ext4 485M 40M 421M 9% /boot
/dev/sdc1 ext4 20G 421M 19G 3% /home
/dev/mapper/mail_store-mbox ext4 119G 188M 112G 1% /mailbox
[root@test2 jason]#