vgcreate failing

[Anu Mathew]

Hi folks,

I was trying to create a volume group which is of 160GB size and it failed giving a "too large" error.

When I tried to re-create the same VG with PE size of 16 it worked.

Is it not possible to create VGs of PE size 4 if the VG size is considerably big?

Thanks a lot for you patience and time,

Anu Mathew

[James R. Ferguson]

Hi Anu:

LVM requires that its internal tables fit within one physical extent on a disk. The 'max_pv', 'max_lv' and 'pe_size' factor affect this table size.

Increasing your 'pe_size' is one way around your problem.

...JRF...

[Anu Mathew]

Hi James,

Thanks for the reply. Increasing the PE size has worked for me.

Is that the only way to get around?

Regards

Anu Mathew

[James R. Ferguson]

Hi Anu:

It's possible to circumvent the one-extent restriction by adjusting one or more of the parameters 'max_pv', 'max_pe', and 'pe_size',

The LVM table is restricted to one extent where the table size is essentially (max_pe * max_pv). 'max_pe' can range from 1-65535 and 'max_pv' from 1-255 -- quite a range. The problem is that once the volume group is created, non of these attributes can be changed, so be careful how you configure things.

See the man pages for 'vgcreate' for more details, too.

...JRF...

[Patrick Wallek]

Here is a link to a good document out on the TKB that discusses this exact problem:

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=c9778a220cd7c874c2/screen=ckiDisplayDocument?docId=200000054599371

Essentially you have to make the extent that the LVM data structures fit into larger, or make the LVM data structures smaller, or both, by altering one, or all, of the parameters max_lv, max_pv and pe_size.