I was in smit, checking on disc space, etc. and it appears that one of our physical volumes that is part of a large volume group, has no free physical partitions. The server is running AIX 5.1. What would be the advisable step to take in this instance?

I have to guess. You need more space to increase a filesystem right ?. Add another disk, Or if you can remove some filesystems [ not used / unwanted ] that will free up some space.

I am not too sure if this is what you wanted, As your question is not very clear. So reply in the aix section with more details and we should be able to help you in a better way.

it doesn't matter if a pv has no free pps left, as long there is space in the volume group (lsvg <vgname>) and you extend a filesystem, the logical volume automatically uses the free pps on another free disk, expect you have limited the lvs max pvs or maxpps

sometimes it's not wise to just extend a fs, for example when you have a disk to filesystem-policy

Thanks for your replies. I admittedly am a beginner with UNIX. I have lots of experience with Windows file systems, and am trying to understand how UNIX allocates PP's. The volume group that this PP is a part of contains a total of 2710 PP's, 1913 used, and 797 free. So I'm guessing that we are not in imminent danger of running out of disc space. They are spread out over five physical volumes. This is volume 3. So in my simplistic understanding of UNIX file allocation, whatever file systems that are mounted on disk 3 are full, so UNIX will automatically allocate space on the other disks?

i'll get you some links tomorrow for aix lvm basics

or use "man lvm"

just a few commands:

lslv -l <lvname> shows the disks a lv lies on

lspv -l <hdiskname> shows which lvs are on a disk

lsvg -l <vgname> shows the lvs a volume group consists of and the lvs filesystems

when a fs lies on hdisk5 and hdisk3, and hdisk5 is full, it uses hdisk3 to "grow"
when you extend it - you have to do that manually with "smitty jfs2" for example

Couple questions, what happens if you don't extend it, and when the next physical volume fills up, will I need to extend it again? Also, does the number of free PP for a filesystem need to be checked manually or is there a report that can be run? Lastly, when I extend the filesystem, do I need to shut down the processes running on the filesystem? Again, thanks for bearing with my lack of experience. We have 10 Windows server, and this lone UNIX box.