merge 2 LVMs both have data and on same Volume Group without data loss

Question

I have 2 lvm partitons on the same volume group and im wondering if i can merge them to one lvm without data loss

the way i know that i have to create a new physical volume and extend the volume group with that new one and then resize the lvm with the new size and in that case i have to lose my data in order to resize

thanks in advance.

Answer 1

IF, the logical volumes are on different volume groups and you want to merge them, use the vgmerge command:

First, deactivate the volume group that will be merged into another:

[root@host ~]# vgchange -a n vg_to_be_merged

After that, test if there is no inconsistence that will prevent you from merging:

[root@host ~]# vgmerge -t -v dest_vg vg_to_be_merged

Now, do the merge for real:

[root@host ~]# vgmerge -v dest_vg vg_to_be_merged
    Checking for volume group "dest_vg"
    Checking for volume group "vg_to_be_merged"
    Archiving volume group "vg_to_be_merged" metadata (seqno 2).
    Archiving volume group "dest_vg" metadata (seqno 13).
    Writing out updated volume group
    Creating volume group backup "/etc/lvm/backup/dest_vg" (seqno 14).
  Volume group "vg_to_be_merged" successfully merged into "dest_vg"

However, merging LVM volumes will have no magic trick, since they have filesystems on top of them, and a lot of thinkering with data moving and resizing will be needed.

Further Reading:

• vgmerge(8) manpages
• Merging volume groups on RHEL