AIX LVM Commands

There are many ways to perform LVM functions in AIX.

Logical Track Group When the LVM receives a request for an I/O, it breaks the I/O down into what is called logical track group (LTG) sizes before it passes the request down to the device driver of the underlying disks. The LTG is the maximum transfer size of an LV and is common to all the LVs in the VG. AIX 5L Version 5.2 accepted LTG values of 128 KB, 256 KB, 512 KB, and 1024 KB. However, many disks now support transfer sizes larger than 1 MB. To take advantage of these larger transfer sizes and get better disk I/O performance, AIX 5L Version 5.3 accepts values of 128 KB, 256 KB, 512 KB, 1 MB, 2 MB, 4 MB, 8 MB, and 16 MB for the LTG size.

PV List	lspv
PV Disk Device List	lsdev -Cc disk
VG List	lsvg
VG LV List	lsvg -l rootvg
VG PV List	lsvg -p rootvg
LV List	lslv foo

VG Configuration Limits (AIX 5.3)

VG type	Maximum PVs	Maximum LVs	Maximum PPs per VG	Maximum PP size
Normal VG	32	256	32,512 (1016 x 32)	1 GB
Big VG	128	512	130,048 (1016 x 128)	1 GB
Scalable VG	1024	4096	2,097,152	128 GB

LVM Create:

/usr/sbin/mkvg -y vg -s PP_size diskA

LV Create:

/usr/sbin/mklv -t jfs2 -y lv vg size

Filesystem Create:

/usr/sbin/crfs -v jfs2 -d /dev/lv -m /dir -A yes -p rw -a agblksize=4096 -a logname=INLINE

Where size can be

M/m	MB
G/g	GB
nothing	PP size

Filesystem Size Change

chfs -a size=Xunits filesystem

or (increase)

chfs -a size=+Xunits filesystem

or (shrink)

chfs -a size=-Xunits filesystem

where unit is:

syntax	unit
M	MB
G	GB
nothing	512-byte blocks