lvextend error

[arkie]

Hi All,

I am trying to extend an LV (/dev/vgqs_sapdata/sapdata) but getting the following message:-

lvextend -L 229264 /dev/vgqs_sapdata/sapdata
Warning: rounding up logical volume size to extent boundary at size "229280" MB for striping.
lvextend: Not enough free physical extents available.
Logical volume "/dev/vgqs_sapdata/sapdata" could not be extended.
Failure possibly caused by strict allocation policy

There are 4094 Free PEs available also (which I have just allocated from storage). vgdisplay output is given below:-

root@qx01smx:/>vgdisplay /dev/vgqs_sapdata
--- Volume groups ---
VG Name /dev/vgqs_sapdata
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 255
Cur PV 14
Act PV 14
Max PE per PV 2048
VGDA 28
PE Size (Mbytes) 8
Total PE 28658
Alloc PE 24564
Free PE 4094
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 1.0.0

What might be the problem?

Pl extend your help

[stephen peng]

post lvdisplay -v /dev/vgqs_sapdata/sapdata. I just wondering whether the lv was mirrored and the actual size of the lv was not 196512m before.

[stephen peng]

maybe you've got lv sapdata mirrored, so you could not extend the lv size by allocating the space using by mirrored copy.

[stephen peng]

and please do not post all the lvdisplay -v output, it would be so huge, just two pages.

[singh sanjeev · Accepted solution]

Post the Lvdisplay -v ,information, it will provide us the more info to look at LVM struacture..like strict/pv-strict or distrubuted logic is used.

[Aneesh Mohan]

Hi,


You have only total free PE 32752 MB and you are trying to allocate 229280 MB , ofcourse you have tried to allocated more than what you are avilable with.

Reduce the LV size < 32752 MB


Aneesh

[R.K. #]

Hi Arkie,

>> lvextend -L 229264 /dev/vgqs_sapdata/sapdata

>> lvextend: Not enough free physical extents available.


>> PE Size (Mbytes) 8
>> Free PE 4094

As said..
You have only 4094*8 = 32752Mb free
So you have only about 32 Gb free in your VG..and you are trying to extend it to 229Gb....need to extend the VG...add a disk/lun, then proceed.

[arkie]

Hi Everyone,

root@qx01smx:/>lvdisplay /dev/vgqs_sapdata/sapdata
--- Logical volumes ---
LV Name /dev/vgqs_sapdata/sapdata
VG Name /dev/vgqs_sapdata
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule striped
LV Size (Mbytes) 196512
Current LE 24564
Allocated PE 24564
Stripes 4
Stripe Size (Kbytes) 4096
Bad block on
Allocation strict
IO Timeout (Seconds) default

Sorry, I wont be able to post the 'lvdisplay -v /dev/vgqs_sapdata/sapdata' anymore, as the LV has been extended.

Here, I would request your inputs:-

Initially 2 LDEVs were allocated and I was trying to `lvextend` with them and it was not happening. (NB: the vg got extended). Later, observing the `strict allocation policy` violation, checked the above 'lvdisplay' output and marked the following:-
...
Stripes 4
...
Allocation strict

So, I tried by allocating 2 more LDEVs from the XP12k - extended the VG vgqs_sapdata with the same. And this time `lvextend` worked.

I would like to gather your inputs on this - Is what was done correct?

Where can I learn about the various allocation policies?

[arkie]

Someone pls help me with this...

Could this LVOL have been created with something like :-

lvcreate -s y -i 4 -d p -n sapdata /dev/vgqs_sapdata

I am trying to figure out how the LVOL was created... as this is the first i faced such a situation. This is my understanding - have to assign new disks in groups of 4, if we have to add space (after consuming all allocated PEs)

Will appreciate inputs very much

[stephen peng]

post vgdisplay -v vgqs_sapdata.
why you could not post lvdisplay -v /dev/vgqs_sapdata/sapdata when it was extended?

[singh sanjeev]

Please try to extend the LV with small unit ,like add 1GB to existing size of LV , it will do the trick, then in term of 10GB ,etc.

[R.K. #]

Hi Again,

Information about striping:
http://docs.hp.com/en/B2355-90672/ch08.html

Command may be something like:
#lvcreate -s y -i 4 -I 4 -n sapdata /dev/vgqs_sapdata

>> have to assign new disks in groups of 4, if we have to add space
Yes

[singh sanjeev]

>> as the LV has been extended.
OK
Here, I would request your inputs:-

Initially 2 LDEVs were allocated and I was trying to `lvextend` with them and it was not happening. (NB: the vg got extended). Later, observing the `strict allocation policy` violation, checked the above 'lvdisplay' output and marked the following:-
...
>>Stripes 4
As four disk has been used while creation of lv ,stripes configuration has been used.
4 disk with stripe size of 4096

lvcreate -s y -i 4 -I 4096 -n sapdata/dev/vgqs_sapdata
...



>>>I would like to gather your inputs on this - Is what was done correct?
yes what you have done is correct.

>>Where can I learn about the various allocation policies
A: man page of lvcreate

[arkie]

Hi Stephen,

Sorry, thought you were asking for the o/p before extension. Current `vgdisplay -v vgqs_sapdata` o/p excerpt is below (complete o/p attached):-

root@qx01smx:/>vgdisplay -v vgqs_sapdata
--- Volume groups ---
VG Name /dev/vgqs_sapdata
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 255
Cur PV 16
Act PV 16
Max PE per PV 2048
VGDA 32
PE Size (Mbytes) 8
Total PE 32752
Alloc PE 28160
Free PE 4592
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0
VG Version 1.0.0

--- Logical volumes ---
LV Name /dev/vgqs_sapdata/sapdata
LV Status available/syncd
LV Size (Mbytes) 225280
Current LE 28160
Allocated PE 28160
Used PV 16


--- Physical volumes ---
...

R.K. >> thanks for the same.

Sanjeev >>

Please try to extend the LV with small unit ,like add 1GB to existing size of LV , it will do the trick, then in term of 10GB ,etc.

I would have wanted to check it this way, but it is not possible - it's in PRD

[stephen peng]

I think sanjeev point you out the right way

[R.K. #]

Hello,

Acc to vgdisplay output all disks disk104, disk105, disk108, disk109 have "Free PE=1148" ie 8.9Gb each.
So you can extend you LV upto this amount more (keeping in mind the striping policy).

Regds..

[Chandrahasa s]

Try this

Presently pe allocated=28160

free =4592

Total =32752
32752*8
262016

so you can extend lv as


lvextend -l 32752 /dev/vggs_sapdata/sapdata
or
lvextend -L 62016M /dev/vggs_sapdata/sapdata

Chandra

[stephen peng]

I do consider that arkie have reached what he needed for enlarging the volume. and for those four PVs which has free PEs, all free PEs could be extended to the lv, that means, 73472m. To my understanding, Stripes value: 4, means when you want to to extend this volume, you should have four PVs which has free PEs, though I still do not confirm yet.:)

[stephen peng]

sorry, i made a mistake, the volume could be 36736m larger than now

[arkie]

lvcreate -s y -i 4 -I 4096 -n sapdata/dev/vgqs_sapdata

I would like to ask ... for what kind of applications do we need to set up such LVs ? What are the preferences under various requirement scenarios. .e.g., sap, web/email apps, other general filesystems, etc. ?

[singh sanjeev]

vcreate -s y -i 4 -I 4096 -n sapdata/dev/vgqs_sapdata

>>>I would like to ask ... for what kind of applications do we need to set up such LVs ? What are the preferences under various requirement scenarios. .e.g., sap, web/email apps, other general filesystems, etc. ?

ANswer :
Striping is generally use for the application which have have high disk read/write operation.
as striping increasing the r/w operation and reduce the bottleneck problem with disk utilization.

So striping is done to increase the overall performance of application.

Cheers:

[stephen peng]

simple words: stripe lv's PE to spread i/o, for me, it maybe a better way to improve LUN's i/o performance of XP by spread LUN from one CU:LDEV to different vg.