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 |
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 |