With pvmove achieve online data relocation

This document (000020303) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise Server for SAP Applications 12
SUSE Linux Enterprise Server for SAP Applications 15

Situation

There is not enough space for the PVs(sdc|sdd) in a VG, it is necessary to move part/all of the PEs to other PV(sde)

# pvs
  PV         VG  Fmt  Attr PSize  PFree 
  /dev/sdc   vg1 lvm2 a--   8.00m     0 
  /dev/sdd   vg1 lvm2 a--   8.00m     0 
  /dev/sde       lvm2 ---  30.00m 30.00m
# dd if=/dev/zero of=/mnt/img bs=1M count=15
# df -Th /mnt
Filesystem          Type  Size  Used Avail Use% Mounted on
/dev/mapper/vg1-lv1 ext4   15M   15M     0 100% /mnt
# pvdisplay /dev/sd{c,d} |grep PE 
  PE Size               4.00 MiB
  Total PE              2
  Free PE               0
  Allocated PE          2
  PE Size               4.00 MiB
  Total PE              2
  Free PE               0
  Allocated PE          2

Resolution

Observe the changes of physical extents (PEs) in each PV to verify the working process of 'pvmove'

Scenario 1:
Use 'pvmove' to move physical extents to destination PV

# pvdisplay /dev/sd{c,d} |grep PE 
  PE Size               4.00 MiB
  Total PE              2
  Free PE               0
  Allocated PE          2
  PE Size               4.00 MiB
  Total PE              2
  Free PE               0
  Allocated PE          2

# vgextend vg1 /dev/sde
  Volume group "vg1" successfully extended

# pvmove /dev/sdd /dev/sde
  /dev/sdd: Moved: 100.00%

# pvdisplay /dev/sd{c,d,e} |grep PE
  PE Size               4.00 MiB
  Total PE              2
  Free PE               0
  Allocated PE          2
  PE Size               4.00 MiB
  Total PE              2
  Free PE               2
  Allocated PE          0
  PE Size               4.00 MiB
  Total PE              7
  Free PE               5
  Allocated PE          2

Scenario 2:
Use 'pvmove' from one single Physical Volume to multiple different Physical Volumes

# pvdisplay /dev/sdc |grep 'Total PE'
  Total PE              2

# pvmove /dev/sdc:0 /dev/sdd
  /dev/sdc: Moved: 100.00%
# pvmove /dev/sdc:1 /dev/sde
  /dev/sdc: Moved: 100.00%

# pvdisplay /dev/sd{c,d,e} |grep PE
  PE Size               4.00 MiB
  Total PE              2
  Free PE               2
  Allocated PE          0
  PE Size               4.00 MiB
  Total PE              2
  Free PE               1
  Allocated PE          1
  PE Size               4.00 MiB
  Total PE              7
  Free PE               4
  Allocated PE          3

Tips
Large PV capacity for the real environment, pvmove command can take a long time to execute, you may want to run the command in the background to avoid display of progress updates in the foreground.
# pvmove -b /dev/sdX /dev/sdY
The following command reports the progress of the pvmove command as a percentage at ten second intervals.
# pvmove -i5 /dev/sdZ

Cause

Not enough Free PE to carry new data

Additional Information

More usage, please refer to the EXAMPLES chapter

# man pvmove
EXAMPLES
Move all physical extents that are used by simple LVs on the specified PV to free physical extents elsewhere in the VG.
pvmove /dev/sdb1

Use a specific destination PV when moving physical extents.
pvmove /dev/sdb1 /dev/sdc1

Move extents belonging to a single LV.
pvmove -n lvol1 /dev/sdb1 /dev/sdc1

Rather than moving the contents of an entire device, it is possible to move a range of physical extents, for example numbers 1000 to 1999 inclusive on the specified
PV.
pvmove /dev/sdb1:1000-1999

A range of physical extents to move can be specified as start+length. For example, starting from PE 1000. (Counting starts from 0, so this refers to the 1001st to the
2000th PE inclusive.)
pvmove /dev/sdb1:1000+1000

Move a range of physical extents to a specific PV (which must have sufficient free extents).
pvmove /dev/sdb1:1000-1999 /dev/sdc1

Move a range of physical extents to specific new extents on a new PV.
pvmove /dev/sdb1:1000-1999 /dev/sdc1:0-999

If the source and destination are on the same disk, the anywhere allocation policy is needed.
pvmove --alloc anywhere /dev/sdb1:1000-1999 /dev/sdb1:0-999

The part of a specific LV present within in a range of physical extents can also be picked out and moved.
pvmove -n lvol1 /dev/sdb1:1000-1999 /dev/sdc1

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

Document ID:000020303
Creation Date: 28-Jun-2021
Modified Date:30-Jun-2021
- SUSE Linux Enterprise Server
- SUSE Linux Enterprise Server for SAP Applications

< Back to Support Search

For questions or concerns with the SUSE Knowledgebase please contact: tidfeedback[at]suse.com