VG extension

 
jeevanandham
Frequent Advisor

VG extension

Hi Team,
I have a doubt in vgextension,

I have done a vg extension in one of our hpux server which is in production environment.
activity is extending a filesystem from 10GB to 15 GB (increasing 5GB )of particular filesystem

i have 639 PE in a VG Each PE= 16 MB

639x16=10224 MB

i need to extend 5GB (5120 mb)

so 10224+5120 = 15344 mb

when i execute
lvextend -L 15344 /dev/vgname/lvname

it throws error as

lvextend: Not enough free physical extents available.
Logical volume "/dev/vgsappbi/lvsappbi" could not be extended.
Failure possibly caused by strict allocation policy

then i executed

lvextend -L 15328 /dev/vgname/lvname

it extended successfully

what happened to 15344 -15328 = 16 MB (1 PE)
can any one clear my doubt ? how its happened
Please....
12 REPLIES 12
Robert-Jan Goossens
Honored Contributor

Re: VG extension

Hi,

Could you post the output of

# vgdisplay -v vg_name
# lvdisplay -v /dev/vg_name/lv_name

Regards,
Robert-Jan
Hakki Aydin Ucar
Honored Contributor

Re: VG extension

You have probably run out of your device belong to Hard Disk. You can see this by issuing:

lvdisplay -v /dev/vgname/lvname
jeevanandham
Frequent Advisor

Re: VG extension

Ya i agree that its out of space availability,

the thing is when it alloted 10GB the available PE was only 639 =10224,
10GB =10240-10224 =16 here also i missing 1PE

and when i extend 5GB 5120MB

that is 10+5 =15GB
10240+5120 =15360MB

But here is

10224 +5104 =15328 MB

each time 1 PE is losing

LV availability is only 639 when it was 10 GB

jeevanandham
Frequent Advisor

Re: VG extension

This is when the file system was 10GB (before extending to 15 GB)
#
# vgdisplay -v /dev/vgsappbi
--- Volume groups ---
VG Name /dev/vgsappbi
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 50
Cur PV 1
Act PV 1
Max PE per PV 1016
VGDA 2
PE Size (Mbytes) 16
Total PE 639
Alloc PE 639
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vgsappbi/lvsappbi
LV Status available/syncd
LV Size (Mbytes) 10224
Current LE 639
Allocated PE 639
Used PV 1


--- Physical volumes ---
PV Name /dev/dsk/c4t1d6
PV Name /dev/dsk/c6t1d6 Alternate Link
PV Name /dev/dsk/c8t1d6 Alternate Link
PV Name /dev/dsk/c10t1d6 Alternate Link
PV Status available
Total PE 639
Free PE 0
Autoswitch On
Hakki Aydin Ucar
Honored Contributor

Re: VG extension

So from your opinion, (I am not sure just thinking) system does not give all free bytes as it holds 1 PE for some reasons such as some LV data backup or something ..
jeevanandham
Frequent Advisor

Re: VG extension

Ya me too think that system holds 1 PE for some precaution purpose, but i need to confirm this...

Did anybody have any idea about this and help me out

Thanks in advance......
Hakki Aydin Ucar
Honored Contributor

Re: VG extension

Check:

pvdisplay /dev/dsk/cXtXd0 to see if you still can see free PE ?
Hakki Aydin Ucar
Honored Contributor

Re: VG extension

And besides note that:

if you cannot see your disk cXtXdX with command

# pvdisplay /dev/dsk/cXtXdX

issue the command:

# vgdisplay -v |grep "PV Name" to see if your disk is in the list, if not it is not a member of LVM Group.
jeevanandham
Frequent Advisor

Re: VG extension

i think those commands will not help me to know about the missing PE.. because in availability PE itself its not showing the full size... my question is why its taking one PE in hide but when i increase by 1PE its extending without any cross cut.