vgcreate fails with larger Physical volume

[Yash_2]

I am using HP-ux 11.0 . As root, I issued the command vgcreate -p 50 /dev/vguse /dev/dsk/c1t0d1. The Physical Volume c1t0d1 had already been created. However the vgcreate command failed. The same command worked for smaller PVs, but this one was 52G in size.

I then tried to create the volume group through sam and it worked. As seen from the syslog.log, the command that sam ran to create the VG was :
vgcreate -e 12756 -l 255 -p 16 -s 4 /dev/vguse /dev/dsk/c1t0d1

According to the vgcreate documentation, the default value for max_pe is adjusted to match the physical volume size, which means the -e switch would have taken the value 12756 when I manually ran the command. The value for -l is 255 by default. The only difference is in the -p option.

What might be the reason behind the failure of the command with my supplied arguments?

[Stanimir]

Hi!
I suppose the option -p is
related not for phis.extends, but
for the NUMBER of PV's in VG /32 by default/.
So 50 is very big value.
Regards,Stan

[Yash_2]

I know that the -p option IS for max number pf Physical volumes. The default value is 16. But the same command, with -p 50 worked for smaller PVs. So 50 is not a very high value. Anyway, the valid value for -p ranges from 1 to 255.

[Michael Tully]

The -e option sets 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). Even so the limit has been reached with your arguments. The -p 16 is the default.

[Jean-Louis Phelix]

Hi,

In fact it doesn't work simply because you would need too many pe's (VGRA size would be too big). If you increase the pe size (for example to 8 or 16), you will be able to use '-p 50'.

Regards.

[Yash_2]

-e max_pe
??
Set 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.

[Armin Feller]

Could you please provide the command you are using and the error message. I think LVM gets problems with the VGRA.

[Armin Feller]

It is possible to have large -e and -p values but you must also increase -s (pe_size) as this will allow a larger extent to put the VGRA tables in. And the VGRA can only be in one PE.

Regards ...
Armin

[Michael Steele_2]

Question: "File too large error" indicated during vgcreate failure?

Most of what you need has been presented in the above posts but there is also a formula and a couple of guidelines that you can use for calculating PE_SIZE. Here is the formula:

2 * ( 30 + MAX_PE ) / 1024 = PE_SIZE

Here is one guideline:

If the size of any PV's in the VG exceed 1016 * PE_SIZE then increase MAX_PE, else, ignore MAX_PE.

Here is a 2nd guideline:

If you have smaller PV's already configured in the VG then vgcreate will fail.

And yes, PE_SIZE can only be a power of 2, 1,2,4,8,16,32,64,128,256.

And yes, the default MAX_PE = 1016

This is all you need.