Disk size in Volume Group

[Javier Ortiz Guajardo]

I have a Volume Group with 3 Disks, one disk size is 8628 Mb size, this disk was removed from this Volume Group and added to other VG, but the size is now 8624.
Both VG´s are in the same machine.
Why the system do that?
The disk is an EMC.
Than

[Navin Bhat_2]

Could you please post the output of vgdisplay and lvdisplay?

[Javier Ortiz Guajardo]

here you are!!

[Patrick Wallek]

I have a feeling it is related to the physical extent size (PE Size line of 'vgdisplay' of each VG.

With the original VG, I bet the PE Size was 4 MB. 8628 / 4 = 2157 extents per disk.

With the new VG, I bet the PE Size is 8 MB. 8624 / 8 = 1078 extents per disk. 8628 will NOT divide evenly by 8 (8628/8=1078.5), thus you sacrifice 4MB since you can NOT have a partial extent.

Check the vgdisplay output for each VG and note the PE Size. That should explain it.

[Sanjay_6]

Never worried much about 4MB. Why go for all the pain in identifying why i'm not getting 4mb from a disk.

A logical reason could be that the new vg to which this disk got added can support only 8624MB disk and any usable space more that that on the disk will be discarded. This is controlled by the Max PE per PV parameter for the VG. Do a vgdisplay for the new VG and check and see what this parameter is over there.

Hope this helps.

Regds

[David Child_1]

Try the following:

1. diskinfo /dev/rdsk/c#t#d# (where c#t#d# is the disk showing as 8628Mb)

2. diskinfo /dev/rdsk/c#t#d# (where c#t#d# is the disk showing as 8624Mb)

Compare the two outputs. Since these are EMC disks it is possible that they are not the same size on the EMC frame.

Is this a Symmetrix/DMX or Clariion/CX array?

David

[iminus]

Do a pvdisplay on the disk to see if it actually been used for other logical volume or not.