Can you create a mirror copy of an LV while it is online?

[susan.derose]

Hi,

I am not 100% sure, but there should be no reason why you can't create a mirror copy of an already existing LV online under vg00, correct?

The current LV size is 5GB and I see that I have 4319PE free and PE size for the VG is 16MB. So I should have roughly 1GB free left over after the mirroring of this LV on diskA to the target diskB.

lvcraete -m 1 /dev/vg00/lv_name /dev/disk/diskB ?
Can I do that while /dev/vg00/lv_name is online? If it makes any difference, I do have jfsonline.

Susan

[James R. Ferguson · Accepted solution]

Hi Susan:

Yes, you most certainly can mirror a logical volume when it is "online".

In fact, to mirror a logical volume, the volume group must be activated or "online".

OnlineJFS has no relationship to mirroring. LVM mirrors are strictly at the logical volume layer.

You can add ('lvextend') or remove ('lvreduce') mirrors at any time.

Regards!

...JRF...

[susan.derose]

Thank you James, for confirming that for me.