*Logical Volume Manager
# smitty lvm
Logical Volume Manager
Move cursor to desired item and press Enter.
Volume Groups
Logical Volumes
Physical Volumes
Paging Space
*SMIT volume group menu
# smitty vg
Volume Groups
Move cursor to desired item and press Enter.
List All Volume Groups
Add a Volume Group
Set Characteristics of a Volume Group
List Contents of a Volume Group
Remove a Volume Group
Activate a Volume Group
Deactivate a Volume Group
Import a Volume Group
Export a Volume Group
Mirror a Volume Group
Unmirror a Volume Group
Synchronize LVM Mirrors
Back Up a Volume Group
Remake a Volume Group
Preview Information about a Backup
Verify the Readability of a Backup (Tape only)
View the Backup Log
List Files in a Volume Group Backup
Restore Files in a Volume Group Backup
*Adding a volume group to the system
# smitty mkvg
Add a Volume Group
Move cursor to desired item and press Enter.
Add an Original Volume Group
Add a Big Volume Group
Add a Scalable Volume Group
Add an Original Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes. [Entry Fields]
VOLUME GROUP name [datavg]
Physical partition SIZE in megabytes +
* PHYSICAL VOLUME names [hdisk1 hdisk2] +
Force the creation of a volume group? no +
Activate volume group AUTOMATICALLY yes +
at system restart?
Volume Group MAJOR NUMBER [] +#
Create VG Concurrent Capable? no +
*Adding a scalable volume group to the system
# mkvg -S -y db2_vg hdisk3 (or)
# smitty mkvg
Add a Volume Group
Move cursor to desired item and press Enter.
Add an Original Volume Group
Add a Big Volume Group
Add a Scalable Volume Group
Add a Scalable Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
VOLUME GROUP name [db2_vg]
Physical partition SIZE in megabytes +
* PHYSICAL VOLUME names [hdisk3] +
Force the creation of a volume group? no +
Activate volume group AUTOMATICALLY yes +
at system restart?
Volume Group MAJOR NUMBER [] +#
Create VG Concurrent Capable? no +
Max PPs per VG in units of 1024 32 +
Max Logical Volumes 256 +
Enable Strict Mirror Pools No +
*Listing volume groups and VG attributes
# lsvg
rootvg
datavg
db2_vg
# lsvg -o
datavg
rootvg
# lsvg rootvg
VOLUME GROUP: rootvg VG IDENTIFIER: 00c8c36600004c000000013068f60d16
VG STATE: active PP SIZE: 512 megabyte(s)
VG PERMISSION: read/write TOTAL PPs: 1116 (571392 megabytes)
MAX LVs: 256 FREE PPs: 58 (29696 megabytes)
LVs: 16 USED PPs: 1058 (541696 megabytes)
OPEN LVs: 15 QUORUM: 1 (Disabled)
TOTAL PVs: 2 VG DESCRIPTORS: 3
STALE PVs: 0 STALE PPs: 0
ACTIVE PVs: 2 AUTO ON: yes
MAX PPs per VG: 32512
MAX PPs per PV: 1016 MAX PVs: 32
LTG size (Dynamic): 1024 kilobyte(s) AUTO SYNC: no
HOT SPARE: no BB POLICY: relocatable
PV RESTRICTION: none
*Listing PVs in a VG and VG contents
# lsvg -p rootvg
rootvg:
PV_NAME PV STATE TOTAL PPs FREE PPs FREE DISTRIBUTION
hdisk0 active 558 57 00..00..00..00..57
hdisk1 active 558 1 00..00..00..00..01
# lsvg -l rootvg
rootvg:
LV NAME TYPE LPs PPs PVs LV STATE MOUNT POINT
hd5 boot 1 2 2 closed/syncd N/A
hd6 paging 44 88 2 open/syncd N/A
hd8 jfs2log 1 2 2 open/syncd N/A
hd4 jfs2 148 296 2 open/syncd /
hd2 jfs2 20 40 2 open/syncd /usr
hd9var jfs2 20 40 2 open/syncd /var
hd3 jfs2 20 40 2 open/syncd /tmp
hd1 jfs2 79 158 2 open/syncd /home
hd10opt jfs2 20 40 2 open/syncd /opt
hd11admin jfs2 1 2 2 open/syncd /admin
fwdump jfs2 2 4 2 open/syncd /var/adm/ras/platform
lg_dumplv sysdump 4 4 1 open/syncd N/A
livedump jfs2 1 2 2 open/syncd /var/adm/ras/livedump
fslv00 jfs2 200 200 1 open/syncd /ptc
fslv02 jfs2 120 120 1 open/syncd /oracle
fslv03 jfs2 20 20 1 open/syncd /ftp
*Change a volume group
# smitty chvg
Change a Volume Group
Type or select a value for the entry field.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [datavg] +
Change a Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name datavg
* Activate volume group AUTOMATICALLY yes +
at system restart?
* A QUORUM of disks required to keep the volume no +
group on-line ?
Convert this VG to Concurrent Capable? no +
Change to big VG format? no +
Change to scalable VG format? no +
LTG Size in kbytes 1024 +
Set hotspare characteristics n +
Set synchronization characteristics of stale n +
partitions
Max PPs per VG in units of 1024 32 +
Max Logical Volumes 256 +
Mirror Pool Strictness +
(or)
# chvg -a y -Q n datavg
*Extend and reduce a VG
(1) Add a Physical Volume to a Volume Group
extendvg [-f] Volumegroup hdiskn
(2) Remove a Physical Volume from a Volume Group
reducevg [-d] [-f] Volumegroup hdiskn
The -d option deallocates the existing logical volume partitions, and then deletes resultant empty logical volumes from the specified physical volumes. User confirmation is required unless the -f flag is added.
# extendvg -f rootvg hdisk2
# lsvg -p rootvg | awk '{print $1, $2}'
rootvg:
PV_NAME PVSTATE
hdisk0 active
hdisk1 active
hdisk2 active
# reducevg -f rootvg hdisk1
# lsvg -p rootvg | awk '{print $1, $2}'
rootvg:
PV_NAME PVSTATE
hdisk0 active
hdisk2 active
*Remove a volume group
# reducevg -df db2_vg hdisk2 hdisk3 (or)
# smitty reducevg2
Remove a Volume Group
Type or select a value for the entry field.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [db2_vg] +
*Activate and deactivate a volume group
# varyonvg datavg
# varyoffvg datavg
(or)
# smitty varyonvg
Activate a Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [datavg] +
RESYNCHRONIZE stale physical partitions? yes +
Activate volume group in SYSTEM no +
MANAGEMENT mode?
FORCE activation of the volume group? no +
Warning--this may cause loss of data
integrity.
Varyon VG in Concurrent Mode? no +
Synchronize Logical Volumes? no +
# smitty varyoffvg
Deactivate a Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [datavg] +
Put volume group in SYSTEM no +
MANAGEMENT mode?
*Import and export a volume group
(1) Exporting a volume group
If you have a volume group on one or more external disks that you want to access on another system, you must first export the volume group from the current system using the exportvg command. This removes all information about the volume group from the system. To export a volume group, it must be inactive.
# exportvg datavg (or)
# smitty exportvg
Export a Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [datavg] +
(2) Importing a volume group
To access an exported volume group on a system , it must be imported to the system using the importvg command.
Never attempt to import rootvg.
# importvg -y datavg hdisk3 (or)
# smitty importvg
Import a Volume Group
Type or select values in entry fields.
Press Enter AFTER making all desired changes.
[Entry Fields]
VOLUME GROUP name [datavg]
* PHYSICAL VOLUME name [hdisk3] +
Volume Group MAJOR NUMBER [] +#
*Reorganize a Volume Group
# reorgvg rootvg (or)
# smitty reorgvg
Reorganize a Volume Group
Type or select a value for the entry field.
Press Enter AFTER making all desired changes.
[Entry Fields]
* VOLUME GROUP name [rootvg] +
*LVM and RAID support
(1) LVM supports the following three software RAID configurations:
- RAID 0, Striping
- RAID 1, Mirroring (up to 3 copies)
- RAID 10 or 1+0, Striping + Mirroring
(2) Striping aides performance, whereas mirroring aides availability.
(3) In today's environment , most data resides in SANs. Disks in a SAN are generally grouped together into a RAID array and divided ito LUNs.
- AIX sees LUNs as physical disks.
- One should not further deploy AIX RAID configruations on top of H/W (SAN) RAID configurations.
- SAN environments provide greater levels of RAID support. (performance and availability)
- LUNs can be increased in size, if so AIX must know about it: # chvg -g datavg
*LVM options which affect performance
(1) Inter- and intra-policy
Logical volume placement on disk
(2) Scheduling policy
Dictates how data is read/written for mirrored LVs
(3) Mirror write consistency
Ensures mirrored PPs are consistent
(4) Write verify
Verifies all writes with a read operation
Default is no. Generally it is not recommended to set to yes as it will impact system (write) performance.
*Logical volume placement
(1) Intra-physical volume allocation policy
(2) Inter-physical volume allocation policy
- Minimum (default)
`1 LV copy. One (or minimum) PV should contain all PPs.
`2 or 3 LV copies. Use as many PVs as copies, keeping PV usage down to a minimum.
- Maximum
`PPs should be spread over as many PVs as possible.
Note: These settings have little effect when used in SAN environments, whereby LUNs are in RAID configurations.