Maximum PEs per Logical Volume

[dandoff]

I am trying to extend a Logical volume, however I am getting the following error:

lvextend: "LogicalExtentsNumber" is bigger than the maximum value allowed.

The PE size for my volume group is 4MB. My question is what is the maximum number of Physical Extents/Logical Extents per logical volume with a PE size of 4MB and a max PE per PV of 8543?

What is the formula for determining the maximum number of Physical Extents you can have for a given PE size?

[Pete Randall · Accepted solution]

"My question is what is the maximum number of Physical Extents/Logical Extents per logical volume with a PE size of 4MB and a max PE per PV of 8543?"

The max PE per LV in this case is just what you said it was: 8543. It is set at vg creation. The PE size does not enter in unless you're trying to calculate the maximum physical volume size, then it is simply PE size times max PE.


Pete

[Robert-Jan Goossens_1]

Hi,

Take a look at this doc.

lvextend: "LogicalExtentsNumber" is bigger than the maximum DocId: KBRC00014448

http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000079994968

Regards,
Robert-Jan

[dandoff]

Thanks Pete.

My problem is that I am unable to increase the filesystem in question beyond 255 GB. What is preventing me from going beyond that point? I have plenty of physical volumes.

[Tiziano Contorno _]

As far as I know LE number is limited to 65535. Ther's no relation to MAX PE per PV. Maybe you are trying to lvextend the volume to more LE than you have.

[James R. Ferguson]

Hi:

A logical volume size of 256GB would be met with a PE size of four (4) and 65,535 extents. That is an implementation limit.

Once set, during 'vgcreate', the values of 'pe_size', 'max_pv', 'max_lv' and 'max_pe' cannot be changed.

Regards!

...JRF...

[dandoff]

Thanks Robert, so I see from the knowledge base document that I am limited to a maximum logical volume size of 262140 MB when I have PE size of 4 MB.

How is the maximum logical extents number of 65535 determined?

[James R. Ferguson]

Hi (again):

As noted, 65,535 is a ceiling. It's 2**16-1 so you can see that the limitation is fixed to the number of bits allocated for tracking the number of extents in the volume group "header".

Regards!

...JRF...

[dandoff]

Thanks everyone, I am going to create a new vg with a PE size of 8 Mbytes, I appreciate the prompte responses.

[dandoff]

Thanks everyone, I am going to create a new vg with a PE size of 8 Mbytes, I appreciate the prompt responses.

[dandoff]

I have found a solution, I am going to create a new volume group with a larger PE size of 8 Mbytes

[Patrick Wallek]

If you are gonig to have large LV's and large PV's, you may be better off by creating your new VG with a PE size of 32. That will give quite a bit of growth room, if necessary.