Replace PV in Maxed out VG

[trisco]

I have a need to replace an existing hdisk with another one. That need is due to some reconfiguration of the SAN luns. The PV is not bad. The volume group is at its maximum amount of physical volumes. Only one jfs2 file system (lv) is wholly contained on this disk. There are other lvs in this VG that are not affected. Since I can't add another PV to the VG, does anyone have suggestions as to how to minimize the outage of the application?

One option is to
1) backup the fs
2) delete fs
3) reducevg
4) rmdev
5) extendvg with replacement lun
6) restore the fs
7) mount the fs
Does anyone know of other options available to me?

Thanks for any comments regarding the above steps or other
actions.

 

[p5wizard]

One option is if you can free up another PV (or more) by creating another temp VG and moving some LVs while they are not in use (unmounted, closed, whatever...). Then reducevg the freed PVs and bring in the big PV so you can migrate the LV to the new PV.

Or if you have one or more mirrored LVs in the VG, you can empty PVs by unmirroring one or more LVs.



HTH,

p5wizard

 

[trisco]

Thank you p5wizard.

The VG is not mirrored so freeing up a mirrored PV is not possible. You've given me an idea. Instead of freeing up an existing used PV, why can't I allocate a new VG with the new PV, create a unique fs there, copy the LV (cplv), remove the orig. fs and lun, then rename the new fs to the desired one.

Then I have the moved fs in another VG. That is not such a big issue.

 

[p5wizard]

If you create and mount the new FS, any method for copying the contents of the existing FS to the new FS will do. Personally I would use cp -R, not cplv...

It is good practice to have some headroom in a VG - i.e. keep it less than 32 PVs as you have now found out, or free PPs on each PV so you can modify the VG to a "Big VG" or "Scalable VG"...


HTH,

p5wizard