topic Re: calculating LV SIZE in Operating System - HP-UX

calculating LV SIZE

seenivasan — Mon, 13 Dec 2010 11:01:49 GMT

Dear All,

while i am reading doc it was mentioned before creating LV we nned to know PE size.Depending upon the PE size we need to creat lV.
From following o/p can you clarify.

#vgdisplay -v /dev/vg01
--- Volume groups ---
VG Name /dev/vg01
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 1
Act PV 1
Max PE per PV 1016
VGDA 2
PE Size (Mbytes) 4
Total PE 477
Alloc PE 475
Free PE 2
Total PVG 0

--- Logical volumes ---
LV Name /dev/vg01/lvol1
LV Status available/syncd
LV Size (Mbytes) 1900
Current LE 475
Allocated PE 475
Used PV 1

--- Physical volumes ---
PV Name /dev/dsk/c1t1d0
PV Status available
Total PE 477
Free PE 2

Re: calculating LV SIZE

Torsten. — Mon, 13 Dec 2010 11:13:14 GMT

Maybe I don't understand your question, but the size is written there:

LV Size (Mbytes) 1900

Its the Current LE (475) * PE size (4MB)

Re: calculating LV SIZE

rariasn — Mon, 13 Dec 2010 11:31:04 GMT

Hi:

You can create lvol in 2 different ways:

# lvcreate -n lvol1 -l 475 ...
# lvcreate -n lvol1 -L 1900 ...

man lvcreate

rgs,

Re: calculating LV SIZE

seenivasan — Mon, 13 Dec 2010 11:42:46 GMT

Dear the question is how to calculate and create a LV?

Re: calculating LV SIZE

Pete Randall — Mon, 13 Dec 2010 11:54:50 GMT

How much data do you want to put in this LV? If you want it to contain 1900 MB, then you're perfect. If you want it to contain more, then you're going to need to make it bigger (hint, see lvextend).

Pete

Re: calculating LV SIZE

seenivasan — Mon, 13 Dec 2010 12:03:12 GMT

Dear ,

My question is If i need to create new LV then how to calcuate LV size?Don't consider the above o/p.

Re: calculating LV SIZE

Torsten. — Mon, 13 Dec 2010 12:07:01 GMT

It depends on your requirements.

With lvcreate you can specify the number of PE or the size in MB.

Re: calculating LV SIZE

Bijeesh — Mon, 13 Dec 2010 12:12:34 GMT

Hi,

From vgdiaplsy o/p,
free PE = 2
Size of one PE = 4 mb

So the size of the LV that can be created, is 2*4 = 8 mb.

You have already an LV which have 475 PEs .

>>Depending upon the PE size we need to creat LV<<
Either you can mention the LV size in mb using -L option or with the number of PEs with -l option with lvcreate command.

Eg.
If you have free PE= 25
and PE size = 4 mb ,
then your total free size is 25*4 = 100 mb
So with -l option, mention 25
and with -L option, mention 100

Re: calculating LV SIZE

seenivasan — Mon, 13 Dec 2010 13:07:56 GMT

Dear Thanks a lot.Now i am very clear.