physical extent

[Gurudatta Shinde]

Why I can not create file system more than 262 GB
with Physical extent size of 4MB in HP-UX 11 OS ?

[Torsten.]

Hi,

run "vgdisplay -v" and calculate *your* maximum, like:

PE Size (Mbytes) 16
Total PE 4319

[Gurudatta Shinde]

Hi ,
Vgdisplay -v cmd is ok .but I want to know
that what are restrictions on PE size while using HP-UX 11 os.
thanks

[Torsten.]

regarding pe_size:

the number of megabytes in each physical extent, where pe_size is expressed in units of megabytes (MB) in the range 1 to 256. pe_size must be equal to a power of 2 (1, 2, 4, 8, etc.). The default value for pe_size is 4 (four megabytes).

(man vgcreate)

regarding max_pe:

the maximum number of physical extents that can be allocated from any of the physical volumes in the volume group. The default value for max_pe is 1016. However, if the size of any physical volume exceeds 1016 times the pe_size, the default value for max_pe is adjusted to match the physical volume size. The maximum number of physical extents can be a value in the range 1 to 65535.

This gives a maximum of 16TB.
(at least for 11iv3)

[Bill Hassell]

4Mb extents are the smallest allocation unit for a Physical extent. Since the space to hold the bookeeping for extents is fixed, only 65,535 extents can ever be created. That's why you must plan ahead for growth and large volume groups. If you need hundreds to thousands of Gb, create the volume group with 16K or even 32k Physical extents.

The man page for vgreate is useful for the options.

[Gurudatta Shinde]

Hi Bill,
Ur answer was satisfactory.
But is it possible to make PE of size 16k or 32k as u said in 11 version ?
Thks
Regards

[Bill Hassell]

As always, the man page is useful. According to the man page, you can specify up to 256 megs. In my previous post, I mentioned 16k or 32k -- that should be 16 or 32 to specify PE size in megabytes. In 11.00, the maximum filesystem sizes are:

128Gb for HFS
1Tb for VxFS *if* you have JFS 3.3 and create a version 3 or 4 filesystem. JFS 3.3 is an extra product (but not likely available anymore as HP-UX 11.00 is obsolete). Here are the details:

http://docs.hp.com/en/5971-2383/5971-2383.pdf

[Gurudatta Shinde]

Hi Bill
Now I am 100% satisfied with your answers thaks a lot
I am closing this thread
Best regards

[Gurudatta Shinde]

Hi all
Thanks to all.I got my query solved
So I am closing this thread.