[linux-lvm] calculating free capacity from pvdisplay and lvdisplay

Rahul Nabar rpnabar at gmail.com
Wed Aug 11 17:03:39 UTC 2010

On Wed, Aug 11, 2010 at 1:10 AM, Ray Morris <support at bettercgi.com> wrote:

Thanks Giorgio and Ray! That helps!
> df shows that your LVs take up 8.6TB: 6TB + 600 GB + 2 TB.
> Therefore, you are using 8.6TB of disk space for those LVs.
> Some of the space WITHIN each LV might not be used for files,
> but it has been dedicated to that LV.

Makes sense! The only reason that I was confused was why 3 of my PV's
say "yes (but full)" and the other three not. How does one explain

1.63x3=4.89 still less than 8.6.

Has the VG spanned across the first 3 PVs fully and then utilized the
remaining 3 partially?

> I'm not good at explaining things, so sometimes I try explaining three
> different ways.  I have six cereal boxes, each half empty.  I put the
> boxes in a bag.  The bag is now full.  The cereal boxes may not be full,
> but they fill up the bag.  The cereal boxes are your half empty LVs and
> the bag is your drives.

Food based analogies are always good! :)


The vgs output is exactly as you say:

[root at eustorage ~]# vgs
  VG                      #PV #LV #SN Attr   VSize VFree
  euclid_highperf_storage   6   3   0 wz--n- 9.80T 1.22T


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