creation of PVG based VG

[Sreer]

Hi Gurus,
Its for my testing based environment.
I have a 11.31 box
with two controllers.
my plan is I should have a PVG as below:

VG vg0x
PVG pvg1
/dev/dsk/c3t2d0
PVG pvg2
/dev/dsk/c5t0d2

I need to create a VG with the pvg based.
I have checked many docs but not getting the exact one to begin my learning in lvm pvg
I tried as
after creating the vg controlfile,tried to create vg:
vgcreate -s 64 -g pvg1 pvg2 /dev/vg01 /dev/dsk/c3t2d0
/dev/dsk/c5t0d2

but its not working..

could you guide me on this?


In short my requirement is to create a vg with pVG policy.

Rgds
Sree

[vishnu.khandare]

Hi Sree,

U have PV:/dev/dsk/c3t2d0
PV:/dev/dsk/c5t0d2

To create a VG fro this two PV, run belo commands,
#pvcreate -f /dev/rdsk/c3t2d0
#pvcreate -f /dev/rdsk/c5t0d2
#mkdir /dev/vg0X ; X u can give any no
#mknod /dev/vg0X/group c 64 0x0X0000
#vgcreate -p 60 -s PE_size -e 12500 /dev/vg0X /dev/dsk/c3t2d0
/dev/dsk/c5t0d2
Now this will create a VG vg0X
U can create logival volume under it as per ur req.

Hope this solves ur query.

Regards
Vishnu Khandare

[Sreer]

Hi Vishu,
Thnaks for the reply.
What you given is a normal vg creation..But my requirement is a vg with PVG!!!!

Rgds
Sree

[Manix · Accepted solution]

The pvgs must have been created like this
vgcreate -g pvg1 /dev/vgname /dev/dsk/c5t8d0 /dev/dsk/c5t9d0
vgextend -g pvg2 /dev/vgname /dev/dsk/c7t1d0 /dev/dsk/c7t2d0

Then when creating volumes you can do
lvcreate -m 1 -n volname -L size_in_mb -s g /dev/vgname

id you want to do RAID 0 + 1 then you can
mention "-s g & -D Y" while lv creation
but then you need at least two disks in each PVG as shown.

[nijokj]

PVGs are usually used to group PV by controller to increase performance. LV can be mirrored two different PVGs. This is controlled by the -s option (strictness) of lvextend -m

As per your scenario

VG vg0x
PVG pvg1
/dev/dsk/c3t2d0
PVG pvg2
/dev/dsk/c5t0d2

# vgcreate -g pvg1 -s 32 /dev/vg0x /dev/dsk/c3t2d0

vgextend -g pvg2 -s 32 /dev/vg0x /dev/dsk/c3t2d0

lvcreate -m 1 -s g -L size -n lv_name /dev/vg0x

[Torsten.]

No no no.

This will create a VG "pvg1", not a PVG!

The lvmpvg file is a plain text file.
You need to create it (by vi or ...).

For 2 disks it doesn't make much sense.


VG vg0x
PVG pvg1
/dev/dsk/c3t2d0
PVG pvg2
/dev/dsk/c5t0d2



With some more disks it makes much more sense.

It is basically used to mirror "pvg1" to "pvg2" without specifying the certain disks.


See the man page also!

[Torsten.]

Sorry, I really need to clean my glasses ...

[Sreer]

Hi,

All I succeeded to create the VG with Pvg characteristics.
now my querry is :

do we need minimum 2 disks in each pvg to full fill the lv creation with PVG characteristics????

Or tleast 1 disk is enough ?

I tried to use just 10 LEs but Iam getting errors!!!

# lvcreate -n lvdata -l 10 -s g -D y /dev/vg0x
Logical volume "/dev/vg0x/lvdata" has been successfully created with
character device "/dev/vg0x/rlvdata".
lvcreate: Not enough free physical extents available.
Logical volume "/dev/vg0x/lvdata" could not be extended.
Failure possibly caused by PVG-Strict or Distributed allocation policies.
[rx26-206]/
#

But see there is enough space in both disks.

# vgdisplay -v /dev/vg0x
--- Volume groups ---
VG Name /dev/vg0x
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 0
Open LV 0
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 1093
VGDA 4
PE Size (Mbytes) 64
Total PE 1156
Alloc PE 0
Free PE 1156
Total PVG 2
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 1.0
VG Max Size 1093g
VG Max Extents 17488


--- Physical volumes ---
PV Name /dev/dsk/c5t0d3
PV Status available
Total PE 63
Free PE 63
Autoswitch On
Proactive Polling On

PV Name /dev/dsk/c3t2d0
PV Status available
Total PE 1093
Free PE 1093
Autoswitch On
Proactive Polling On


--- Physical volume groups ---
PVG Name pvg1
PV Name /dev/dsk/c5t0d3

PVG Name pvg2
PV Name /dev/dsk/c3t2d0

Thnx for help

Rgds
Sree

[Manix]

>># lvcreate -n lvdata -l 10 -s g -D y /dev/vg0x

as i said earlier if you are using " -D y"
distributive extent based striping you need
even no of disks at each PVG.

for PVG strict mirror - what you want to do as
told so far,i think below command should work


# lvcreate -n lvdata -l 10 -s g /dev/vg0x