Linux LVM全面实践

1.磁盘分区

[root@ol6-121-rac1 ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xd8bb2864.
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 (1-1305, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-1305, default 1305): +5G

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 2
First cylinder (655-1305, default 655):
Using default value 655
Last cylinder, +cylinders or +size{K,M,G} (655-1305, default 1305):
Using default value 1305

Command (m for help): p

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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: 0xd8bb2864

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         654     5253223+  83  Linux
/dev/sdb2             655        1305     5229157+  83  Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
[root@ol6-121-rac1 ~]# partprobe
Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy).  As a result, it may not reflect all of your changes until after reboot.
Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0 has been opened read-only.
[root@ol6-121-rac1 ~]# fdisk -l /dev/sdb

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 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: 0xd8bb2864

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         654     5253223+  83  Linux
/dev/sdb2             655        1305     5229157+  83  Linux

2.创建PV

[root@ol6-121-rac1 ~]# pvcreate /dev/sdb{1,2}

  Physical volume "/dev/sdb1" successfully created
  Physical volume "/dev/sdb2" successfully created
[root@ol6-121-rac1 ~]# pvscan
  PV /dev/sda2   VG vg_ol6121rac1   lvm2 [11.51 GiB / 0    free]
  PV /dev/sdb1                      lvm2 [5.01 GiB]
  PV /dev/sdb2                      lvm2 [4.99 GiB]
  Total: 3 [21.50 GiB] / in use: 1 [11.51 GiB] / in no VG: 2 [10.00 GiB]
[root@ol6-121-rac1 ~]# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               vg_ol6121rac1
  PV Size               11.51 GiB / not usable 3.00 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              2946
  Free PE               0
  Allocated PE          2946
  PV UUID               YEG40A-wEWW-9F8Z-bgcL-PWvA-7sef-FP12my

  "/dev/sdb1" is a new physical volume of "5.01 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb1
  VG Name
  PV Size               5.01 GiB
  Allocatable           NO
  PE Size               0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               p2nXS7-MmpX-Pawj-ThU3-k1NQ-t5Rc-hqKtb4

  "/dev/sdb2" is a new physical volume of "4.99 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/sdb2     ----PV名
  VG Name                             ----分配的VG，因为没有分配，所以是空
  PV Size               4.99 GiB      ----PV的大小
  Allocatable           NO            ---是否被分配
  PE Size               0             ---PE的大小
  Total PE              0             ----共分配的PE数
  Free PE               0             ----没有被LV用掉的PE
  Allocated PE          0             ----尚可被分配的PE数量
  PV UUID               M31k1o-JGJx-3OrN-DmNf-W8uJ-SXBB-JdSviW
 由于PE是在创建VG的时候才指定，所以这里的PE都显示0
[root@ol6-121-rac1 ~]# pvdisplay     ---这里显示已经被VG使用的PV（与上面做个对比）
  --- Physical volume ---
  PV Name               /dev/sdb1
  VG Name               datavg
  PV Size               5.01 GiB / not usable 10.10 MiB
  Allocatable           yes
  PE Size               512.00 MiB
  Total PE              10
  Free PE               10
  Allocated PE          0
  PV UUID               p2nXS7-MmpX-Pawj-ThU3-k1NQ-t5Rc-hqKtb4  

3.创建VG

创建格式：vgcreate -s N[mgt] VG名称 PV名称

[root@ol6--rac1 ~]# vgcreate -s 512M datavg /dev/sdb1   ---“-s”后面加PE的大小，单位可以是m,                                                                                  g,t
  Volume group "datavg" successfully created
[root@ol6--rac1 ~]# vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "datavg" using metadata type lvm2
  Found volume group "vg_ol6121rac1" using metadata type lvm2
[root@ol6--rac1 ~]# pvscan
  PV /dev/sdb1   VG datavg          lvm2 [5.00 GiB / 5.00 GiB free]
  PV /dev/sda2   VG vg_ol6121rac1   lvm2 [11.51 GiB /     free]
  PV /dev/sdb2                      lvm2 [4.99 GiB]     ---,没有被使用的PV
  Total:  [21.49 GiB] / in use:  [16.51 GiB] / in no VG:  [4.99 GiB]
[root@ol6--rac1 ~]# vgdisplay datavg
  --- Volume group ---
  VG Name               datavg
  System ID
  Format                lvm2
  Metadata Areas
  Metadata Sequence No
  VG Access             read/write
  VG Status             resizable
  MAX LV
  Cur LV
  Open LV
  Max PV
  Cur PV
  Act PV
  VG Size               5.00 GiB
  PE Size               512.00 MiB
  Total PE
  Alloc PE / Size        /
  Free  PE / Size        / 5.00 GiB
  VG UUID               wtuMSA-qOM7-eslo-BeiR-N8pJ-PVic-ZQXDXu
扩展VG
[root@ol6--rac1 ~]# vgextend datavg /dev/sdb2
  Volume group "datavg" successfully extended
[root@ol6--rac1 ~]# vgdisplay datavg
  --- Volume group ---
  VG Name               datavg
  System ID
  Format                lvm2
  Metadata Areas
  Metadata Sequence No
  VG Access             read/write
  VG Status             resizable
  MAX LV
  Cur LV
  Open LV
  Max PV
  Cur PV
  Act PV
  VG Size               9.50 GiB
  PE Size               512.00 MiB
  Total PE
  Alloc PE / Size        /
  Free  PE / Size        / 9.50 GiB
  VG UUID               wtuMSA-qOM7-eslo-BeiR-N8pJ-PVic-ZQXDXu

4.创建LV

创建格式：lvcreate -L N[mgt] -n LV名称 VG名称   或者  lvcreate -l N -n LV名称 VG名称
说明：-L 后面加容量  -l 后面加PE的个数
[root@ol6--rac1 ~]# lvcreate -L 5G -n datalv datavg   创建一个5G的LV
  Logical volume "datalv" created
[root@ol6--rac1 ~]# vgdisplay datavg
  --- Volume group ---
  VG Name               datavg
  System ID
  Format                lvm2
  Metadata Areas
  Metadata Sequence No
  VG Access             read/write
  VG Status             resizable
  MAX LV
  Cur LV
  Open LV
  Max PV
  Cur PV
  Act PV
  VG Size               9.50 GiB
  PE Size               512.00 MiB
  Total PE
  Alloc PE / Size        / 5.00 GiB
  Free  PE / Size        / 4.50 GiB
  VG UUID               wtuMSA-qOM7-eslo-BeiR-N8pJ-PVic-ZQXDXu

[root@ol6--rac1 ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/datavg/datalv
  LV Name                datalv
  VG Name                datavg
  LV UUID                sZ5JSE-YkRc-QxLA-GzWT-lLSR-s0WY-b0R8Pv
  LV Write Access        read/write
  LV Creation host, time ol6--rac1.localdomain, -- :: +
  LV Status              available
  # open
  LV Size                5.00 GiB
  Current LE
  Segments
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to
  Block device           :

[root@ol6--rac1 ~]# ll /dev/datavg/datalv
lrwxrwxrwx  root root  Mar  : /dev/datavg/datalv -> ../dm-
删除LV：lvremove /dev/datavg/datalv  ---注意：要加绝对路径
扩展LV
[root@ol6--rac1 ~]# lvresize -l + /dev/datavg/datalv   绝对路径
  Extending logical volume datalv to 9.50 GiB
  Logical volume datalv successfully resized
[root@ol6--rac1 ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/datavg/datalv
  LV Name                datalv
  VG Name                datavg
  LV UUID                j5Wvb3-ZFiz-5PyG-gfdp-NPb4-BdRq-PhT1wm
  LV Write Access        read/write
  LV Creation host, time ol6--rac1.localdomain, -- :: +
  LV Status              available
  # open
  LV Size                9.50 GiB
  Current LE
  Segments
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to
  Block device           :

5. 创建文件系统

[root@ol6--rac1 ~]# mkfs -t ext4 /dev/datavg/datalv   ---格式化，注意LV全名
mke2fs 1.41. (-May-)
Filesystem label=
OS type: Linux
Block size= (log=)
Fragment size= (log=)
Stride= blocks, Stripe width= blocks
 inodes,  blocks
 blocks (5.00%) reserved for the super user
First data block=
Maximum filesystem blocks=
 block groups
 blocks per group,  fragments per group
 inodes per group
Superblock backups stored on blocks:
        , , , , , , , 

Writing inode tables: done
Creating journal ( blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every  mounts or
 days, whichever comes first.  Use tune2fs -c or -i to override.
[root@ol6--rac1 ~]# mount /dev/datavg/datalv /oradata/   ---挂载
[root@ol6--rac1 ~]# df -lhT                              ---查看
Filesystem    Type    Size  Used Avail Use% Mounted on
/dev/mapper/vg_ol6121rac1-lv_root
              ext4    .4G  .9G  .1G  % /
tmpfs        tmpfs    499M  100K  499M   % /dev/shm
/dev/sda1     ext4    485M   55M  405M  % /boot
/dev/sr0   iso9660    .5G  .5G      % /media/OL6. x86_64 Disc
/dev/mapper/datavg-datalv
              ext4    .4G  150M  .8G   % /oradata

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Lookers-on see most of the game.-- Smedley

旁观者清

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