Moving part of an lvm vg from one pv to another

Lets say that you’ve got multiple physical volumes (PV) in a Volume Group (VG) and you want to migrate the extents from one PV to another, this can be acomplished with a quick and easy pvmove command.

For example

pvdisplay -m
--- Physical volume ---
PV Name /dev/sdb1
VG Name INTEL_RAID
PV Size 2.73 TiB / not usable 4.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 714539
Free PE 0
Allocated PE 714539
PV UUID XWiRzE-Ol3d-38En-ND6b-qo93-4zeF-xv8zDv

--- Physical Segments ---
Physical extent 0 to 604876:
Logical volume /dev/INTEL_RAID/MEDIA
Logical extents 0 to 604876
Physical extent 604877 to 617676:
Logical volume /dev/INTEL_RAID/backups_mimage_0
Logical extents 25600 to 38399
Physical extent 617677 to 617701:
Logical volume /dev/INTEL_RAID/EPG
Logical extents 0 to 24
Physical extent 617702 to 643301:
Logical volume /dev/INTEL_RAID/backups_mimage_0
Logical extents 0 to 25599
Physical extent 643302 to 714538:
Logical volume /dev/INTEL_RAID/MEDIA
Logical extents 604877 to 676113

--- Physical volume ---
PV Name /dev/sdc1
VG Name INTEL_RAID
PV Size 2.04 TiB / not usable 2.00 MiB
Allocatable yes
PE Size 4.00 MiB
Total PE 535726
Free PE 430323
Allocated PE 105403
PV UUID laOuKy-5FZa-cJ3h-JffV-qUub-diKC-O0wVqK

--- Physical Segments ---
Physical extent 0 to 25599:
Logical volume /dev/INTEL_RAID/backups_mimage_1
Logical extents 0 to 25599
Physical extent 25600 to 54202:
Logical volume /dev/INTEL_RAID/MEDIA
Logical extents 676114 to 704716
Physical extent 54203 to 67002:
Logical volume /dev/INTEL_RAID/NZB_DOWNLOAD
Logical extents 0 to 12799
Physical extent 67003 to 79802:
Logical volume /dev/INTEL_RAID/backups_mimage_1
Logical extents 25600 to 38399
Physical extent 79803 to 105402:
Logical volume /dev/INTEL_RAID/OLD_VM
Logical extents 0 to 25599
Physical extent 105403 to 535725:
FREE

From here you can see that /dev/INTEL_RAID/MEDIA is a Logical Volume (LV) on both PVs within the VG. If I was wanting to grow my mirrored LV, which requires space on both PVs, I’d have to migrate some of the extents of another LV. If I wanted to move some of the MEDIA lv, I should be able to do the following

pvmove /dev/sdb:643302-714538 /dev/sdc

This will move extents 643302-714538 to the next contiguious block on /dev/sdc

Published by

Welby

Welby McRoberts is Lead Infrastrucure engineer at a large managed hosting & cloud computing company working on large-scale deployments and solutions. Follow Welby on Twitter @welbymcroberts or his Personal Site

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