Adding alternate SAN links to lvols

[ConnieK]

I have vgextended 5 disks into one vg. I created a number of raw lvols in this vg. But when I did the lvextend for each one, I forgot to add the alternate paths. Is there a way just to add the alt paths (not mirrored) to the lv's?

[James R. Ferguson]

Hi:

Alternate links, also known as 'pvlinks' are simply addtional paths to a physical volume. You add them with 'vgextend'.

The order of the pvlinks as recoreded for a volume group in '/etc/lvmtab' determines the primary and secondary link. To promote a secondary link to a primary one, 'vgreduce' the primary link and then add it back with 'vgextend'.

Regards!

...JRF...

[ConnieK]

Thanks James, but to clarify, I've already added the addtional pv's in the volume group. I'm asking how to add the alternate paths in for each lvol.

Ive already created the lvols and extended them onto the pv, like this:

lvextend -L 2048 /dev/vg01/lvol1 /dev/dsk/c7t2d0

but neglected to add in the alt paths when I lvextended them. Don't I need to lvextend over all 4 paths - one primary and 3 alternate?

I just need to know how to add the alternate paths onto each lvol.

[James R. Ferguson · Accepted solution]

Hi (again) Connie:

Alternate links relate to a volume group and its physical volumes, not to a logical volume which is a subset of the volume group.

If, however, you have more than one alternate link to the volume group, simply use 'vgextend' to add up to seven alternate links in addition to your primary one.

Within a volume group, every logical volume is accessable by every pvlink to the volume group. There is nothing to do at the logical volume level.

LVM mirroring is done at the logical volume level.

Regards!

...JRF...

[ConnieK]

James - Thank you!!! I guess I thought I had to do the lvols too. DANKE!!!!!

[ConnieK]

Closed -

[skt_skt]

JUST DO
vgextend altpath1pv1 altpath2pv1 altpath1pv2 altpath2pv2 etc VGNAME

That is all u required. go through man page of vgextend/lvextend for any clarification.