[PLUG] problems creating logical volume (LVM)

Jason LaPier jason.lapier at gmail.com
Wed Nov 7 09:53:20 PST 2012


First off -
Bummed that I missed the PLUG talk on LVM - if I'd realized I was going to
need it so soon, I would have gone out of my way to attend! In any case,
Brian Martin's post [1] on the subject is a great read.

So I'm trying to create a logical volume in a volume group that stripes
across a few of Amazon's EBS volumes. When I try this with a couple 1 GB
volumes, it works fine. When I try this with five 1 TB volumes, I'm seeing
a strange error.

$ vgcreate ebs_vg /dev/sdp1 /dev/sdp2 /dev/sdp3 /dev/sdp4 /dev/sdp5
$ vgdisplay /dev/ebs_vg
  --- Volume group ---
  VG Name               ebs_vg
  System ID
  Format                lvm2
  Metadata Areas        5
  Metadata Sequence No  1
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                5
  Act PV                5
  VG Size               4.88 TiB
  PE Size               4.00 MiB
  Total PE              1279995
  Alloc PE / Size       0 / 0
  Free  PE / Size       1279995 / 4.88 TiB
$ lvcreate -l 100%VG -n ebs_lv -i2 ebs_vg -I256
  Rounding size (1279995 extents) up to stripe boundary size (1279996
extents)
  Volume group "ebs_vg" has insufficient free space (1279995 extents):
1279996 required.


I'm expecting it to be smart enough to make it the right size by using the
"100%" for the logical extents. If I try to manually set this to the number
it seems to want, I still get the error:

$ lvcreate -l 1279995 -n ebs_lv -i2 ebs_vg -I256
  Rounding size (1279995 extents) up to stripe boundary size (1279996
extents)
  Volume group "ebs_vg" has insufficient free space (1279995 extents):
1279996 required.

Anyone see anything glaring that I'm missing?

Thanks!

- Jason L.



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