The following are an overview of how to create volumes in LVM for HP-UX.
1) Add your disks, and verify their device names. The the command:
# ioscan -fnC disk
2) Next, place the disks you wish to use for volumes under LVM control. This is done by converting a disk into a “Physical Volume” (pv). The command used is:
# pvcreate <devpath>
example: #pvcreate /dev/rdsk/c1t0d0
Note: You can use the “-f” option to “force” the creation, which keeps LVM for asking for verification…
the “Would you like to proceed? (y/n)”
3) Now, create a device path for the volume group. Do this by creating a directory in /dev by the name of the volume group.
# mkdir /dev/<vgname>
example: # mkdir /dev/vg01
4) Then create a “group node” in that directory. The process looks like this:
# mknod /dev/<vgname>/group c 64 <minornum>
example: # mknod /dev/vg01/group c 64 0x030000
Note: The minor number follows the following patern:
0x030000
0x040000
0x050000
…..
5) You can now create your Volume Group (vg) to which the Physical Volumes will be assigned. A VG
is similar to a Disk Group in Veritas. The format is:
# vgcreate /dev/<vgname> <PVpath> <PVpath> ….
example: # vgcreate /dev/vg01 /dev/dsk/c1t0d0
Note: The PV DevPaths don’t use a partition designation (sX). You can specify as many PV’s to add to a VG as you like on this one line.
6) Next create a Logical Volume (lv). This is the “volume” itself, which will contain the file system.
# lvcreate /dev/<vgname>
example: # lvcreate /dev/vg01
Note: This will create a 0 length volume. It will also create two new files in the vg dev directory: lvol1 and rlvol1. Being: Logical Volume 1, and Raw Logical Volume 1. You can have multiple LV’s per VG.
Note(2): lvcreate with no options will create a concat volume. To create striped volumes, use the options:
-i <stripes> This is the Vx equiv to column numbers.
-I <stripesize> This is the Vx equiv to a stripe width in kb.
-m <mirror copies> Number of mirrors. Can be “1” or “2”.
-L <lv size> The size of the new volume in megabytes.
7) Now you can extend to Logical Volume to the length you desire. To extend to it’s max, do the following:
a) Run the command: # vgdisplay <vgpath> example: # vgdisplay /dev/vg01
b) Look for the two lines: “Total PE” and “PE Size” PE stands for “Physical Extent”. If you multiply the number of “Total PE” by “PE Size” you will get the total size of the disk that is usable, usually in megabytes.
NOTE: LVM breaks PV’s into Physical Extents. These are like blocks in LVM. PE Size is the size of each PE. Total PE is the number of PE’s avalible to the volume group. The “PE Size” is variable, default is “4M” but it can be reset to any desired size, during VG creation. The options avable to “vgcreate” are:
-e <maxpe> Max Num of PE’s for this VG. Default: 1016
Max PE cannot exceed: 65535
-l <maxlv> Max Num of LV’s for this VG. Default: 255
-p <maxpv> Max Num of PV’s for this VG. Default: 16
Max PV cannot exceed: 255
-s <pesize> Size of each PE for this VG. Default: 4
PE Size must be a power of 2.
-x <extensiblity> Can the VG be grown? Default: y
c) With the number you got by multiplying “Total PE” by “PE Size” you have the total lenth of the VG. To make all disks
in the VG be used by 1 LV, and to use all the space, extend the Logical Volume with the command:
# lvextend -L <length> <lvdevpath>
example: # lvextend -L 3200 /dev/vg01/lvol1
This would extend VG01’s LV 1 out to (NOT by) 3.2G. Remember the size is defaulted to Megabytes.
8) You can now create your filesystem with:
# newfs -F <fs> <raw_lvdevpath>
example: # newfs -F vxfs /dev/vg01/rlvol1
9) Now mount the filesystem like usual:
# mount /dev/vg01/lvol1 /mydatavolume
Done!
————————————————————–
NOTES:
– Monitor LVM with the following commands:
bdf Similar to a Solaris style “df -k” output.
pvdisplay Display PV Information
vgdisplay Display VG Information
lvdisplay Display LV Information
– Remove LVM Objects with the commands:
pvremove Removes a PV Device (ie: /dev/dsk/c0t1..)
vgreduce Remove a PV from a VG Binding
use as: vgreduce /dev/vg01 /dev/dsk/c0t1d0
vgremove Removes a VG, only done when there
is only ONE disk left in the VG.
lvremove Removes a LV.
To remove a complete volume you must unmount the fs, then remove the LV, then reduce the VG to all but one disk. Then remove the VG. Then you only need to remove each PV untill you have normal disks again, not under LVM control.
– Here’s a list of commands:
—-VG—–
vgcfgbackup
vgchange
vgcreate
vgexport
vgimport
vgremove
vgcfgrestore
vgchgid
vgdisplay
vgextend
vgreduce
vgscan
—LV—-
lvchange
lvdisplay
lvlnboot
lvreduce
lvrmboot
lvcreate
lvextend
lvmmigrate
lvremove
—PV—-
pvchange
pvck
pvcreate
pvdisplay
pvmove
pvremove
– There are 3 LVM Objects:
—————————-
| Logical Volume |
—————————-
/ / / /
—————————-
| Volume Group |
—————————-
/ / / /
—————————-
| Physical Volume |
—————————-
or: Disks are used to create PV’s, which we group into VG’s, from which we create LV’s which contains the filesystem we use.
– AIX Commands are:
–PV–
chpv
ldeletepv
lquerypv
lspv
replacepv
lchangepv
linstallpv
lresyncpv
migratepv
–VG–
cfgvg
importvg
lsvg
lvgenminor
reorgvg
varyonvg
chvg
lchangevg
lsvgfs
mirrorvg
syncvg
exportvg
lcreatevg
lvaryoffvg
mkvg
unmirrorvg
extendvg
lqueryvg
lvaryonvg
redefinevg
updatevg
getvgname
lqueryvgs
lvgenmajor
reducevg
varyoffvg
–LV–
chlv
getlvodm
lresynclv
lvrelmajor
rmlv
chlvcopy
lchangelv
lslv
lvrelminor
rmlvcopy
clvm_cfg
lchlvcopy
lvaryoffvg
mklv
splitlvcopy
clvmd
lcreatelv
lvaryonvg
mklvcopy
synclvodm
copyrawlv
ldeletelv
lvchkmajor
namerslv
updatelv
cplv
lextendlv
lvgenmajor
putlvcb
extendlv
lmigratelv
lvgenminor
putlvodm
getlvcb
lquerylv
lvlstmajor
readlvcopy
getlvname
lreducelv
lvmmsg