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

Giorgio Bersano giorgio.bersano at gmail.com
Wed Aug 11 08:42:31 UTC 2010

```2010/8/11 Rahul Nabar <rpnabar at gmail.com>

> Some of the physical volumes show "Allocatable           yes (but
> full)" while others don't. How does one relate this to the actual
> capacity? THe reason I am confused is that 3 of my PV's show up as
> full and each is 1.63 TB. Thus the total full space would come to 4.89
> TB. But the sum of full space of all my LV's is only around 3 TB
> (based on the output of df)
>
> I've reproduced the outputs of pvdisplay, lvdisplay and df below.
>
> I'm confused! Any pointers?
>
> --
> Rahul
>
>
Hi Rahul,
you really appear to have 6 PV (not three) of 1.63TB each and all that
storage space is assigned to the VG euclid_highperf_storage .
The VG has three LV defined from it and indeed has free space; using these
LV you  created three filesystems which have free space too, as Ray just
explained.

You have not shown the output of a vgs command but if If you issue it you
should see something like this:

#vgs
VG         #PV #LV #SN Attr   VSize VFree
euclid_highperf_storage  6   3   0 wz--n- 9.8T   1.22T

and so you still have 1.22 TB of free space to use

some math...

Details from pvdisplay:
PE Size (KByte)  4096  = 4MB
VG Name          euclid_highperf_storage
Total PE= 428351*6 = 2570106*4MB = 10280424 MB = 9.8TB
total Free PE: 38140+140607+140607 = 319354*4MB = 1277416M = 1.22 TB
total Allocated PE: 428351*3+390211+287744+287744 = 2250752*4MB = 9003008 MB
= 8.58 TB

Details from lvdisplay:
Current LE     1572864+153600+524288 = 2250752
exactly like the Allocated PE in pvdisplay

Best regards,
Giorgio.

> [root at eustorage ~]# pvdisplay
>  --- Physical volume ---
>  PV Name               /dev/sdb
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes (but full)
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               0
>  Allocated PE          428351
>  PV UUID               wDdbmP-2n5m-98HD-Ewqk-Q3y0-lnMf-rsaVXt
>
>  --- Physical volume ---
>  PV Name               /dev/sdc
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes (but full)
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               0
>  Allocated PE          428351
>  PV UUID               75i75q-2rec-2FMf-eyPa-W0nF-zFHH-PIAvvc
>
>  --- Physical volume ---
>  PV Name               /dev/sdd
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes (but full)
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               0
>  Allocated PE          428351
>  PV UUID               vo2Jh2-PfFC-eOj4-GYnP-Jx1I-Sisu-2nY4lC
>
>  --- Physical volume ---
>  PV Name               /dev/sde
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               38140
>  Allocated PE          390211
>  PV UUID               EK7cvF-IZjf-PJVw-d2RR-lCdt-kOSD-iqFtOf
>
>  --- Physical volume ---
>  PV Name               /dev/sdf
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               140607
>  Allocated PE          287744
>  PV UUID               fQXN8S-HhYu-weoq-kbuz-BrxZ-6WQk-6ydBDw
>
>  --- Physical volume ---
>  PV Name               /dev/sdg
>  VG Name               euclid_highperf_storage
>  PV Size               1.63 TB / not usable 4.00 MB
>  Allocatable           yes
>  PE Size (KByte)       4096
>  Total PE              428351
>  Free PE               140607
>  Allocated PE          287744
>  PV UUID               i7GD1d-rbd2-efKd-uK3u-D3S2-BxJv-UkrNve
>
> [root at eustorage ~]# df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sda2              76G  8.6G   64G  12% /
> /dev/sda6              19G  365M   17G   3% /var
> /dev/sda5              15G  165M   14G   2% /tmp
> /dev/sda1             487M   17M  445M   4% /boot
> tmpfs                  24G     0   24G   0% /dev/shm
> /dev/mapper/euclid_highperf_storage-LV_home
>                      6.0T  1.4T  4.4T  24% /home
> /dev/mapper/euclid_highperf_storage-LV_export
>                      591G   17G  550G   3% /opt
> /dev/mapper/euclid_highperf_storage-LV_polhome
>                      2.0T  1.5T  386G  80% /polhome
> [root at eustorage ~]# lvdisplay
>  --- Logical volume ---
>  LV Name                /dev/euclid_highperf_storage/LV_home
>  VG Name                euclid_highperf_storage
>  LV UUID                gu7yo1-TYYr-ucHG-QSDk-y8HD-ETrs-Z5kCk9
>  LV Status              available
>  # open                 1
>  LV Size                6.00 TB
>  Current LE             1572864
>  Segments               1
>  Allocation             inherit
>  - currently set to     1536
>  Block device           253:0
>
>  --- Logical volume ---
>  LV Name                /dev/euclid_highperf_storage/LV_export
>  VG Name                euclid_highperf_storage
>  LV UUID                1lktLy-Hgn3-qS1m-41VJ-5kNY-DMyb-1ri4Th
>  LV Status              available
>  # open                 1
>  LV Size                600.00 GB
>  Current LE             153600
>  Segments               1
>  Allocation             inherit
>  - currently set to     1536
>  Block device           253:1
>
>  --- Logical volume ---
>  LV Name                /dev/euclid_highperf_storage/LV_polhome
>  VG Name                euclid_highperf_storage
>  LV UUID                xqpOX5-HFey-H0qi-NgjP-NVS7-FwDb-zbiK8m
>  LV Status              available
>  # open                 1
>  LV Size                2.00 TB
>  Current LE             524288
>  Segments               4
>  Allocation             inherit