LVM logical volume management-creation of PV/VG/LV

LVM --- logical volume manager (

Logical Volume Manager
)
.
LVM
This helps us easily allocate storage space for applications and users. In
LVM
The logical volume under management can be changed or removed as needed.
LVM
Storage volumes can also be managed by user groups, allowing administrators to use more intuitive names.
(
For example
"Sales ',
'Development ')
Replace physical disk
(
For example
'Sda ',
'Sdb ')
To identify the storage volume.

 

	Traditional partition Concept	LVM Logical volume Management
Disk Space independence	Cannot be fully utilized, especially for FS Only one partition can be matched.	Multiple Disks PV Storage pool VG And then segment the logical volume according to the application LV Improve space utilization
Spatial scalability	Repartition	Use static or dynamic online expansion of volume group capacity
Data backup	When the business is busy, I/O Frequent interface read/write	Snapshots can be used to capture the instantaneous and precise copy of a logical volume. Online backup has been completed.
User usability	The partition ID cannot meet the requirements of many users.	Can be defined according to user requirements LV Volume label of logical volume

 

I. Preparations for creating LVM
1. Build the environment: OS: rhel5.3
LVM package
IDE disk/dev/HDB (1024 MB),/dev/HDD (1024 MB)
2. Convert disk partitions --> LVM volume partitions
Final Solution:/dev/HDB --> Create/dev/hdb1 (ID: 5, system: Extended)
/Dev/hdb5 (ID: 8e, system: Linux LVM)
/Dev/HDD --> Create/dev/hdd1 (ID: 5, system: Extended)
/Dev/hdd5 (ID: 8e, system: Linux LVM)
Operation: (for example,/dev/HDB)

 

# Fdisk/dev/HDB # P (display partition information) --> # N (create partition) --> # E (create extended partition) --> # L (create logical partition) # Here is the experiment environment to facilitate subsequent increase and decrease operations, so we divide/dev/HDB into one partition. # T (set disk hex code) --> # 8e (linuxlvm) --> # W (save Operation) # P Disk/dev/HDB: 1073 MB, 1073741824 bytes 16 Heads, 63 sectors/track, 2080 Cylinders Units = cylinders of 1008*512 = 516096 bytes Device boot start end blocks ID system /Dev/hdb1 1 2080 1048288 + 5 extended /Dev/hdb5 1 2080 1048257 8e Linux LVM # Partprobe (this command allows the kernel to re-read the disk partition table and the modification takes effect)

 

Ii. Create LVM

1. Create a PV Disk
Solution:/dev/HDB --> lvm2 [1024 MB]
/Dev/HDD --> lvm2 [1024 MB]

Operation:

 

# Pvcreate/dev/hdb5/dev/hdd5 # Pvscan # Pvdisplay "/Dev/hdb5" is a new physical volume of "1023.69 MB" --- New physical volume --- PV name/dev/hdb5 VG name PV size 1023.69 MB Allocatable No PE size (Kbyte) 0 Total pe 0 Free pe 0 Allocated pe 0 Pv uuid zm7103-sjg4-zjob-bel0-dlr1-hhh6-hcg 8kG "/Dev/hdd5" is a new physical volume of "1023.69 MB" --- New physical volume --- PV name/dev/hdd5 VG name PV size 1023.69 MB Allocatable No PE size (Kbyte) 0 Total pe 0 Free pe 0 Allocated pe 0 Pvuuid hAk1Dx-QulA-YV4G-p8wa-7sWw-FiaC-10GorS

 

2. Create a VG storage pool
Solution: lvm2 (/dev/HDB) --> vg1
Lvm2 (/dev/HDD) --> vg2
Operation:

 

# Vgcreate vg1/dev/hdb5 # Vgcreate vg2/dev/hdd5 # Vgscan # Vgdisplay --- Volume group --- VG name vg2 System ID Format lvm2 Metadata areas 1 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 1 Act PV 1 VG size 1020.00 MB PE size 4.00 MB Total PE 255 Alloc PE/size 0/0 Free PE/size 255/1020 .00 MB Vg uuid Wa4Jo8-k3xY-BTng-uV6j-0Ee1-Vp8b-fNVrhQ --- Volume group --- VG name vg1 System ID Format lvm2 Metadata areas 1 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 1 Act PV 1 VG size 1020.00 MB PE size 4.00 MB Total PE 255 Alloc PE/size 0/0 Free PE/size 255/1020 .00 MB Vg uuid UGjfZd-shth-ZRTU-sVVm-MD0s-wzVB-zd7Uwt

 

3. Allocate the LV logical volume
Solution: Work (/dev/hdb5) --> vg1
Study (/dev/hdd5) --> vg2
Operation:

 

# Lvcreate-l 500 m-N work vg1 # Lvcreate-l 500 m-n study vg2 # Lvscan # Lvdisplay   --- Logical volume ---   LV Name                /dev/vg2/study   VG Name                vg2   LV UUID                53VT9v-dyp0-lSST-eDFz-w2Ns-Os0Z-ERnqVU   LV Write Access        read/write   LV Status              available   # open                 0   LV Size            500.00 MB   Current LE         125   Segments               1   Allocation             inherit   Read ahead sectors     auto   - currently set to     256   Block device           253:1   --- Logical volume ---   LV Name                /dev/vg1/work   VG Name                vg1   LV UUID                lhgKVg-hi95-W9gw-wOkZ-uyuy-BgZp-RrsCcA   LV Write Access        read/write   LV Status              available   # open                 0   LV Size            500.00 MB   Current LE         125   Segments               1   Allocation             inherit   Read ahead sectors     auto   - currently set to     256   Block device           253:0

 

4. Partition formatting

 

# Mkfs. Ext3/dev/vg1/work // or # mkfs-J/dev/vg1/work # Mkfs. Ext3/dev/vg2/study //... # DF -L Disk /dev/hda: 8589 MB, 8589934592 bytes 255 heads, 63 sectors/track, 1044 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes     Device Boot Start End  Blocks   Id System /dev/hda1 *     1    32   257008+   83  Linux /dev/hda2     33    97   522112+   83  Linux /dev/hda3     98    358  2096482+ 83  Linux /dev/hda4     359   1044 5510295  5  Extended /dev/hda5     359   549  1534176  83  Linux /dev/hda6     550   848  2401686  83  Linux /dev/hda7     849   913  522081   82  Linux swap / Solaris /dev/hda8     914   978  522081   83  Linux /dev/hda9     979   1043 522081   83  Linux Disk /dev/hdb: 1073 MB, 1073741824 bytes 16 heads, 63 sectors/track, 2080 cylinders Units = cylinders of 1008 * 512 = 516096 bytes      Device Boot Start End   Blocks Id System /dev/hdb1       1    2080 1048288+ 5 Extended /dev/hdb5     1    2080 1048257 8e Linux LVM Disk /dev/hdd: 1073 MB, 1073741824 bytes 16 heads, 63 sectors/track, 2080 cylinders Units = cylinders of 1008 * 512 = 516096 bytes Device   Boot Start End   Blocks  Id  System /dev/hdd1       1   2080 1048288+   5   Extended /dev/hdd5     1   2080 1048257   8e  Linux LVM

 

5. mount a new partition

 

 #mkdir .
.
/
home/work .
.
/
home/study
 #mount .
.
/
dev/vg1/work .
.
/
home/work
 #mount .
.
/
dev/vg2/study .
.
/
home/study
 #df
–Th

Filesystem  Type
  Size
Used Avail Use% Mounted on
/dev/hda2   ext3 494M 212M 257M  46%   /
/dev/hda9   ext3 494M 45M 425M   10%   /var
/dev/hda8   ext3 494M 11M 458M   3%    /opt
/dev/hda6   ext3 2.
3G 68M 2.
1G   4%    /home
/dev/hda3   ext3 2.
0G 1.
7G 182M  91%   /usr
/dev/hda5   ext3 1.
5G 35M 1.
4G   3%    /usr/local

/dev/hda1   ext3 244M 12M 219M   6%    /boot
tmpfs       tmpfs 125M 0  125M   0%    /dev/shm



/dev/mapper/vg1-
work
            ext3  485M 11M 449M  3%    /home/work
/dev/mapper/vg2-
study
            ext3  485M 11M 449M  3%    /home/study