On Mar 10, 8:19 pm, MJB <helios...@cox.net> wrote:
> Hi all,
>
> I have a question on setting up a new LV. Here is some background:
>
> I'm running AIX 5.3TL7 on a p5 system connected to an EMC SAN. I have
> been given a 100GB RAID5 EMC LUN from my storage team. I need to
> create a 100GB filesystem for the Oracle DB. I've created a seperate
> VG named 'oraclevg01' using the hdiskpower I was given. Now, in
> setting up the LV it asks for 'Number of LOGICAL PARTITIONS'. I know
> this cannot exceed the 'MAXIMUM NUMBER of LOGICAL PARTITIONS' but do I

This is not quite correct since this number can be changed.

> I'm not sure what the advantages/penalties may exist for using 1 vs
> 512 for the number of logical partitions when creating the LV.

Initialy - none. If your are using 1 your LV will have the size of 1
PP thus in your case 256 MB if you create afterwards a FS on it will
have the same size.

If needed an FS can be increased with:
$ chfs -a size=50G /MyFS # Will set the size to 50G

or
$ chfs -a size=+50G /MyFS # Will ADD to the current size 50G

and if you hit the 512 LV max size then a

$ /usr/sbin/chlv -x'1024' MyLv

is your friend

Some remarks:
In respect to fs handling on AIX you do not care about disk. You care
about a Volume Groups.
A VG is build of one or more disks and disks can be added to a VG
during runtime.

Now you take parts (slices) out of a VG to build either raw device,
log volumens or filesystem. But no matter what you create they are all
Logical Volumes.
So for a filesystem you need a LV and initialy the maximum size of a
FS is that of the underlying LV. If you need more space for that a
given FS you increase the LV and then the FS. The standard AIX
command chfs does the increase of the LV for you.

Thus you can start with a LV amount of 1. and if increased directly
afterwards you will no problem. Problem might pop up if later other LV
has been created and then you increase the size of a LV. Its because
the PP for that given LV are might scattered around the disk thus
causing performance problems. But for this IAX has the reorgvg
command.

Finaly i see no need for you to rebuild your VG at all.

cheers
Hajo