Originally posted by: dwcasey

After all LV's have been mirrored in rootvg, is there a way to update the free distribution so that they are more evenly distributed? I tried to increased the size of a filesystem and got a message

"There are not enough free partitions or not enough physical volumes to keep strictness and satisfy allocation requests."

It's my understanding that in a mirror setup, you have to have enough free PPs on *both* disks to grow a filesystem. But our distribution looks terrible.

# lsvg -p rootvg
rootvg:
PV_NAME           PV STATE          TOTAL PPs   FREE PPs    FREE DISTRIBUTION
hdisk0            active            558         458         111..57..67..111..112
hdisk1            active            99          3           00..00..00..00..03
 

Originally posted by: The_Doctor

Distribution is more of a performance issue..... you have a functional issue, caused by the relatively small hdisk1.  99 Total PPs with 3 Free PPs on hdisk1 is not enough to satisfy what you are attempting.

Increasing the size of hdisk1 will resolve your issue.  Assuming hdisk1 is a LUN on your SAN, this can be done on the fly.

If you're not comfortable increasing hdisk1 on the fly (some admin's are ok with this and some admin's are not) then allocate a new LUN and then assign this new LUN to "rootvg".

Originally posted by: dwcasey

Extending the LUN isn't a big deal, but hdisk0 has a lot of free space I should be able to use. But since we're mirrored, both have to 'grow' at the same 'rate' if you will.

I wondered about doing a migrate of hd1 for example ( /home ) since that is the one I need to grow. But since it's mirrored, I don't believe that would work.

Why isn't the distribution more even in terms of use between the two hdisks?

Originally posted by: The_Doctor

I'd suggest the distribution pattern only looks uneven given the size difference between hdisk0 and hdisk1.

-- hdisk0 - you have (558-458) 100 PPs used, spread among 558 PPs.  OR conversely 458 FREE PPs spread among 558 available PPs

-- hdisk1 - you have (99-3) 96 PPs used, spread among 99 PPs.  OR conversely 3 FREE PPs spread among 99 available PPs

The distribution pattern would have changed substantially had hdisk1 been closer in size (if not equal in size) to hdisk0 when you created the mirror.

Originally posted by: dwcasey

Ok, that makes sense:

# bootinfo -s hdisk0
286102

# bootinfo -s hdisk1
51200

Originally posted by: The_Doctor

You can also refer to -->

# lslv hd1

and look for -->

EACH LP COPY ON A SEPARATE PV ?: yes 

With this value set to "yes" (the default) LVM will enforce that copies MUST be on separate physical volumes.  Therefore FREE space on hdisk0 is NOT available to /home when hdisk1 runs out of space.

Originally posted by: dwcasey

Ugh...I think I understand the why, but don't like it. So it sounds like even though hdisk1 is ~286G, that I could only grow a filesystem in rootvg ( on those two hdisks as-is ) by 3 more PPs because that is all that hdisk1 has left?

Originally posted by: The_Doctor

ahhhh ......

So it sounds like even though hdisk1 is ~286G,

no..... I think you've reversed the hdisks.   hdisk1 looks like 50GB.  hdisk0 is closer to the ~286GB.

by 3 more PPs because that is all that hdisk1 has left?

correct

I'm NOT recommending this, but if you want to change that behavior, then change this on selective LVs:

EACH LP COPY ON A SEPARATE PV ?: yes

to

EACH LP COPY ON A SEPARATE PV ?: no

Be aware this will permit / create a new set of problems by allowing mirror'd copies to exist on the same physical volume.  Not something you would normally want.

Again, I'd suggest increasing the size of hdisk1 or adding a new LUN is the more acceptable way to resolve your issue.