IBM AIX Logical Volume Manager (LVM)

Components of the LVM

Component	Description
Volume Group (VG)	A collection of one or more physical volumes, independent of type
Logical Volume (LV)	A collection of logical partitions, each of which can be mapped to any physical partition in the volume group. If mirroring is used, the logical partition is mapped to two or three physical partitions.
Logical Partition (LP)	Logical partitions are how logical volumes handle both the mapping to physical partitions on one or more physical volumes and multiple copies for mirroring.
Physical Volume (PV)	A storage device that are divided into physical partitions
Physical Partition (PP)	When you add a physical volume to a volume group, the physical volume is partitioned into contiguous, equal sized units of space called physical partitions. A physical partition is the smallest unit of storage space allocated.
VGDA	Volume group descriptor area.
VGID	The Volume Group Identifier.
PVID	The physical volume identifier.
LVID	The logical volume identifier.
LVCB	The logical volume control block.
VGSA	Volume group status area.

Physical Volume (PV)

Command	Purpose
lspv	Displays information about a physical volume within a volume group. Usage: lspv [-L] [-l|-p|-M] [-n DescriptorPhysicalVolume] [-v VGID] PhysicalVolume
migratepv	Moves allocated physical partitions from one physical volume to one or more other physical volumes. Usage: migratepv [-i] [-l LogicalVolume] SrcPhysicalVolume DestnPV(s)
chpv	Changes the characteristics of a physical volume in a volume group Usage: chpv [-a Allocation] [-v Availability] [-c] PhysicalVolume(s)
replacepv	Replaces a physical volume in a volume group with another physical volume Usage: replacepv [-f] {SourcePV | SourcePVID} DestinationPV Usage: replacepv [-R] dir_name [DestinationPV]

Volume Group (VG)

Command	Propose
extendvg	Adds physical volumes to a volume group Usage: extendvg [-f] VolumeGroup PhysicalVolume(s)
reducedvg	Removes physical volumes from a volume group. Usage: reducevg [-d] [-f] VolumeGroup PhysicalVolume(s)
lsvg	Displays information about volume groups. Usage: lsvg [-L] [-o] | [-n DescriptorPhysicalVolume] | [-i] [-l | -M | -p] VolumeGroup(s)
mkvg	Creates a volume group. Usage: mkvg [-d MaximumPhysicalVolumes] [-B] [-G] [-f] [-i] [-c] [-x] [-m MaxPvSize] [-n] [-s Size] [-t factor] [-V MajorNumber] [-y VolumeGroup] Physical_Volume[s]
exportvg	Export a volume group into the system Usage: exportvg VolumeGroup
importvg	Imports a new volume group definition from a set of physical volumes Usage: importvg [-V MajorNumber] [-y VolumeGroup] [-f] [-c] [-x] | [-L VolumeGroup] [-n] [-F] [-R]PhysicalVolume
varyonvg	Activates a volume group. Usage: varyonvg [-b] [-c] [-f] [-n] [-p] [-s] [-u] VolumeGroup
varyoffvg	Deactivates a volume group. Usage: varyoffvg [-s] VolumeGroup
reorgvg	Reorganizes the physical partition allocation for a volume group. Usage: reorgvg [-i] VolumeGroup [LogicalVolume(s)]
chvg	Changes the characteristics of a volume group Usage: chvg [-a AutoOn {n|y}] [-c|-l] [-Q {n|y}] [-u] [-x {-n|y} ] [-t [factor] ] [-B] VolumeGroup
lsvgfs	Lists the file systems that are in the specified volume group. Usage: lsvgfs VolumeGroup
mirrorvg	Mirrors all the logical volumes that exist on a given volume group. Usage: mirrorvg [-S | -s] [-Q] [-c Copies] [-m] VolumeGroup [PhysicalVolume(s)]
mkvgdata	Creates a file containing information about a volume group for use by the savevg and restvg commands. This file is a symbolic link to the mkszfile script. Usage: mkvgdata [-X] [-m] VGName
redefinevg	Redefines the set of physical volumes of the given volume group in the device configuration database Usage: redefinevg {-d Device | -i Vgid} VolumeGroup
restvg	Restores the user volume group and all its containers and files. Usage: restvg [-b Blocks] [-f Device] [-q] [-s] [-n] [-p PPsize] [PhysicalVolume(s)]
savevg	Finds and backs up all file belonging to a specified volume group. The file is a symbolic link to the mksysb script. Usage: savevg [-b Blocks] [-e] [-f Device] [-i | -m] [-p] [-v] [-X] VGName
syncvg	Synchronizes logical volume copies that are not current. Usage: syncvg [-f] [-i] [-H] [-P NumParallelLPs] { -l LVName(s) | -p PVName(s) | -v VGname(s) }
unmirrorvg	Removes the mirrors that exist on volume groups or specified disks. Usage: unmirrorvg [ -c Copies] VolumeGroup [ PhysicalVolume(s) ]
updatevg	Synchronizes volume group information in the ODM if the ODM has at least a valid volume group identifier. It is an undocumented command Usage: updatevg VGname

Logical Volume (LV)

Command	Propose
mklv	Creates a logical volume. Usage: mklv [-a Position] [-b BadBlocks] [-c Copies] [-d Schedule] [-e Range] [-i] [-L  Label] [-m MapFile] [-r Relocate] [-s Strict] [-t Type] [-u UpperBound] [-v Verify] [-w MirrorWriteConsistency] [-x Maximum] [-y NewLogicalVolume | -Y Prefix] [-S StripeSize] [-U Userid] [-G Groupid] [-P Modes] VolumeGroup NumLP [PhysicalVolume(s)]
cplv	Copy a logical volume to a new logical volume Usage: cplv [-v VolumeGroup] [-y NewLogicalVolume | -Y Prefix] SourceLogicalVolume Usage: cplv -e DestinationLogicalVolume [-f] SourceLogicalVolume
mklvcopy	Provides copies of data with the logical volume. Usage: mklvcopy [-a Position] [-e Range] [-k] [-m MapFile] [-s Strict] [-u UpperBound] LogicalVolume Copies [PhysicalVolume(s)]
chlv	Changes the characteristics of the logical volume[s] Usage: chlv [-n NewLVName] [-a Position] [-b BadBlocks] [-d Schedule] [-e Range] [-G Groupid] [-L label] [-P Modes] [-p Permission] [-r Relocate] [-s Strict] [-t Type] [-U Userid] [-u Upperbound] [-v Verify] [-w MirrorWriteConsistency] [-x Maximum] LogicalVolume[s]
extendlv	Increases the size of a logical volume by adding unallocated physical partitions from within the volume group Usage: extendlv [-a Position] [-e Range] [-u Upperbound] [-s Strict] LPartitions [PhysicalVolume(s)]  Usage: extendlv [-mMapFile] LPartitions
lslv	Displays information about a logical volume. Usage: lslv [-L] [-l|-m] [-n PhysicalVolume] LogicalVolume Usage: lslv [-L] [-n PhysicalVolume] -p PhysicalVolume [LogicalVolume]
readlvcopy	Reads a specific mirror copy of a logical volume. Usage: readlvcopy -d device [-c copy | -C copy | -b] [-n number_of_blocks] [-o outfile] [-s skip] [-S seek]
rmlv	Removes logical volumes from a volume group. Usage: rmlv [-B] [-f] [-p Physical Volume] LogicalVolume(s)
rmlvcopy	Removes copies from a logical volume. Usage: rmlvcopy LogicalVolume Copies [PhysicalVolume(s)]
splitlvcopy	Splits copies from one logical volume and creates a new logical volume from them. Usage: splitlvcopy [-f] [-y NewLVName] [-Y Prefix] LVCopies [PhysicalVolume(s)]
updatelv	Updates the logical control block and the ODM. It is an undocumented command. Usage: updatelv [-c] [-D] [-L] [-P] [-R] LVname VGname

Miscelaneus

Command	Purpose
mkcd	Creates a multi-volume CD (or CDs) from a mksysb or savevg backup image. Usage: mkcd -d cd_device | -S [-m mksysb_image| -M mksysb_target | -s savevg_image | -v savevg_vol_group] [-Ccd_fs_dir] [-I cd_image_dir] [-V cdfs_vol_group] [-G] [-B] [-p pkg_source_dir] [-R | -S] [-i image.data] [-u bosinst.data] [-e] [-P] [-l package_list] [-b bundle_file] [-z custom_file] [-D]
mksysb	Creates an installable image of the root volume group either in a file or onto a bootable tape. Usage: mksysb [-b Number] [-e] [-p] [-v] [-X] [-i | -m] Device | File
mkszfile	Creates a file containing information about the rootvg volume group for use by the mksysb command. Usage: mkszfile [-X] [-m]
synclvodm	Synchronizes or rebuilds the logical volume control block, the device configuration database, and the volume group descriptor areas on the physical volumes. Usage: synclvodm [ -v ] VolumeGroup [ LogicalVolume(s)]

File System (FS)

Command	Purpose
fsck	Checks file system consistency and interactively repairs the file system. Usage: fsck [-n] [-p] [-y] [-dBlockNumber] [-f] [-ii-NodeNumber] [-o Options] [-tFile] [-V VFSName] [FileSystem1 - FileSystem(s)]
crfs	Adds a file system. Usage: crfs -v VfsType {-g VolumeGroup | -d Device} [-l LogPartitions] -m MountPoint [-n NodeName] [-uMountGroup] [-A {yes | no}] [-p {ro | rw}] [-a Attribute= Value ...] [-t {yes | no}]
chfs	Changes attributes of a file system. Usage: chfs [-n NodeName] [-m NewMountPoint] [-u MountGroup] [-A {yes | no}] [-p{ro | rw}] [-t {yes | no} ] [-a Attribute=Value] [-d Attribute] FileSystem
defragfs	Increases a file system's contiguous free space. Usage: defragfs [-q | -r] {Device | FileSystem}
df	Reports information about space on file systems. Usage: df [ [-P] | [-I | -M | -i | -t | -v] ] [-k] [-s] [FileSystem(s) | File(s) ]
dumpfs	Dumps file system information. Usage: dumpfs {FileSystem | Device}
lsfs	Displays the characteristics of file systems. Usage: lsfs [-q] [-c | -l] [-a | -v VFSType | -u MountGroup | [FileSystem(s)]]
mkfs	Makes a file system. Usage: mkfs [-b Boot] [-l Label] [-i i-Nodes] [-o Options] [-p Prototype] [-s Size] [-v VolumeLabel] [-V VFSName]
mount	Makes a file system available for use. Usage: mount [-f] [-n Node] [-o Options] [-p] [-r] [-v VFSName] [-t Type | [Device | Node:Directory] Directory | all | -a [-V [generic_options] special_mount_points]
umount	Unmounts a previously mounted file system, directory, or file. Usage: {unmount | umount} [-f] [-a] | [all | allr | Device | Directory | File | FileSystem | -n Node | -t Type]
rmfs	Removes a file system. Usage: rmfs [-r] FileSystem

Effect of -t factor in chvg

chvg -t factor	Maximun Partitions / PV	Maximun Disks / VG
1	1016	32
2	2032	16
3	3048	10
4	4064	8
5	5080	6
6	6096	5
7	7112	4
8	8128	4
9	9144	3
10	101600	2
16	16256	2

Sources: 
AIX Logical Volume Manager from A to Z: Troubleshooting and Commands (SG24-5433-00)
AIX Logical Volume Manager, from A to Z: Introduction and Concepts ()SG24-5432-00)