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
do not know what I should put here.

Here is some relevant output:
----
lsvg oraclevg01:
VOLUME GROUP: oraclevg01 VG IDENTIFIER:
00c6056000004c000000011899f59f0b
VG STATE: active PP
SIZE: 256 megabyte(s)
VG PERMISSION: read/write TOTAL PPs: 3609
(923904 megabytes)
MAX LVs: 256 FREE PPs:
971 (248576 megabytes)
LVs: 8 USED
PPs: 2638 (675328 megabytes)
OPEN LVs: 8 QUORUM:
4 (Enabled)
TOTAL PVs: 7 VG DESCRIPTORS: 7
STALE PVs: 0 STALE PPs:
0
ACTIVE PVs: 7 AUTO ON:
yes
MAX PPs per VG: 32512
MAX PPs per PV: 1016 MAX PVs: 32
LTG size (Dynamic): 1024 kilobyte(s) AUTO SYNC: no
HOT SPARE: no BB POLICY:
relocatable
----

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.

Any advice will be greatly appreciated.

On Mar 10, 7:19 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
> do not know what I should put here.
>
> Here is some relevant output:
> ----
> lsvg oraclevg01:
> VOLUME GROUP: oraclevg01 VG IDENTIFIER:
> 00c6056000004c000000011899f59f0b
> VG STATE: active PP
> SIZE: 256 megabyte(s)
> VG PERMISSION: read/write TOTAL PPs: 3609
> (923904 megabytes)
> MAX LVs: 256 FREE PPs:
> 971 (248576 megabytes)
> LVs: 8 USED
> PPs: 2638 (675328 megabytes)
> OPEN LVs: 8 QUORUM:
> 4 (Enabled)
> TOTAL PVs: 7 VG DESCRIPTORS: 7
> STALE PVs: 0 STALE PPs:
> 0
> ACTIVE PVs: 7 AUTO ON:
> yes
> MAX PPs per VG: 32512
> MAX PPs per PV: 1016 MAX PVs: 32
> LTG size (Dynamic): 1024 kilobyte(s) AUTO SYNC: no
> HOT SPARE: no BB POLICY:
> relocatable
> ----
>
> 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.
>
> Any advice will be greatly appreciated.

I think you may have the wrong end of this particular stick.

The LV you create will have a total size equal to the number of LPs
multiplied by the size of the LP, which is the same as the size of PP
for the VG. You set the size of PP at VG creation time. Once you have
created the VG, the size of PP is fixed. In this case you don't have a
choice at this stage over the number of LPs to create an LV of size
100GB. Size of LV / Size of LP = Num LPs = 100GB / 256MB = 400 LPs.

Now go back a stage, then you can ask "what PP size should I use to
create a VG which will have LVs of a certain size?". Fragmentation and
possible future growth will partially dictate the answer.

another easier way of saying this is:

You got a volumegroup with PP size of 256 megabyte

It takes 4 LP's to make 1 GB
256 MB * 4 = 1 GB

You need a Logical Volume Group at 100 GB
4 * 100 GB = 400 LP's

Hope this helps
--
Gitte Tøgersen
Denmark


"MJB" <helios123@cox.net> wrote in message
news:64508fe8-0265-468a-8a9c-82bc35a1d211@s50g2000hsb.googlegroups.com...
> 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
> do not know what I should put here.
>
> Here is some relevant output:
> ----
> lsvg oraclevg01:
> VOLUME GROUP: oraclevg01 VG IDENTIFIER:
> 00c6056000004c000000011899f59f0b
> VG STATE: active PP
> SIZE: 256 megabyte(s)
> VG PERMISSION: read/write TOTAL PPs: 3609
> (923904 megabytes)
> MAX LVs: 256 FREE PPs:
> 971 (248576 megabytes)
> LVs: 8 USED
> PPs: 2638 (675328 megabytes)
> OPEN LVs: 8 QUORUM:
> 4 (Enabled)
> TOTAL PVs: 7 VG DESCRIPTORS: 7
> STALE PVs: 0 STALE PPs:
> 0
> ACTIVE PVs: 7 AUTO ON:
> yes
> MAX PPs per VG: 32512
> MAX PPs per PV: 1016 MAX PVs: 32
> LTG size (Dynamic): 1024 kilobyte(s) AUTO SYNC: no
> HOT SPARE: no BB POLICY:
> relocatable
> ----
>
> 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.
>
> Any advice will be greatly appreciated.

On Mar 10, 3:19*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
> do not know what I should put here.
>
> Here is some relevant output:
> ----
> lsvg oraclevg01:
> VOLUME GROUP: * oraclevg01 * * * * * VG IDENTIFIER:
> 00c6056000004c000000011899f59f0b
> VG STATE: * * * * * * *active * * * * * * * * *PP
> SIZE: * * * * * * * * 256 megabyte(s)
> VG PERMISSION: * *read/write * * * * * *TOTAL PPs: * ** * * *3609
> (923904 megabytes)
> MAX LVs: * * * * * * * *256 * * * * * * * * * * FREE PPs:
> 971 (248576 megabytes)
> LVs: * * * * * * * * * * * *8 * * * * * * * * * * * *USED
> PPs: * * * * * * *2638 (675328 megabytes)
> OPEN LVs: * * * * * * *8 * * * * * * * * ** * *QUORUM:
> 4 (Enabled)
> TOTAL PVs: * * * * * * 7 * * * * * * * * * * * *VG DESCRIPTORS: 7
> STALE PVs: * * * * * * 0 * * * * * * * * * * * *STALE PPs:
> 0
> ACTIVE PVs: * * * * * *7 * * * * * * * * * * * *AUTO ON:
> yes
> MAX PPs per VG: * * 32512
> MAX PPs per PV: * * 1016 * * * * * * * * * *MAX PVs: * * * * * * *32
> LTG size (Dynamic): 1024 kilobyte(s) * *AUTO SYNC: * * * * no
> HOT SPARE: * * * * * no * * * * * * * * * * * *BB POLICY:
> relocatable
> ----
>
> 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.
>
> Any advice will be greatly appreciated.

Thanks for the replies. This clears up a lot for me. Luckily this is
not a production server so I can remove and rebuild the VG and LV. I
come from a Soalris background which is simpler than AIX but nowhere
near as flexible. AIX has been a big learning experience to say the
least.

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