lvm and disk space

[Chris Fadrowski]

I recently connected my K class server to Hitachi disk. When i look at sam or vgdisplay it shows that there is no free PE. It states all disk space is being used 100%. But when i do a bdf, it shows differenet and that i have all disk available. there is nothing on this disk at the present time. Can someone elighten me on why LVM does this?

[Helen French]

Hi Chris,

The problem is that the Hitachi disk array ( 7700E ?)you are using is not supported by HP.

Check this document and this thread:

http://us-support.external.hp.com/cki/bin/doc.pl/sid=4d6b7b901324ddfd10/screen=ckiDisplayDocument?docId=200000049196663

http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x127b3f490f4ed61190020090279cd0f9,00.html

HTH,
Shiju

[James R. Ferguson · Accepted solution]

Hi Chris:

'bdf' reports availablity at the filesystem level while 'vgdisplay' reports the availability of physical extents of disk (by default, 4MB each). These physical extents may or may not contain a filesystem. Remember that you start by building a volume group from one or more physical disk with 'vgcreate'. You then create logical volumes on it ('lvcreate') and finally create a filesystem on top with 'newfs'.

Regards!

...JRF...

[G. Vrijhoeven]

Hi,

umount the filesystem, and run an

#extendfs -f vxfs /dev/vg??/lvol?

on the logical volumes, vgdisplay states disk space allocated with logical volume groups, bdf states disk space allocated by filesystems. If that is not the same you file system is smaler than your logical volume.

Gideon

[Helen French]

Hi Chris:

Again, 'vgdisplay' will show no free PE in any disks, if the entire disk is used while creating logical volumes and file systems. This doesn't mean that you don't have free space in the disk, instead it says that there is no room for creating more LVs and file systems.

'bdf' will show the actual file system usage. If it is free it says that you have enough space to store data. The LVM disk creation will be in this order:
1) pvcreate
2) vgcreate ( check vgdisplay here)
3) lvcreate
4) newfs
5) mount
6) bdf

HTH,
Shiju

[harry d brown jr]

Try:

Great topic:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x96b70bce6f33d6118fff0090279cd0f9,00.html
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x316efd3f91d3d5118ff40090279cd0f9,00.html

Great help in finding them:
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x1e6f84534efbd5118ff40090279cd0f9,00.html


live free or die
harry