lvextend a mirrored a lvol

[marvik]

Hi All,

I have a mirrored logical volume.On trying to extend it it gives me below error.Can u advice how to overcome this.

frardb03:/ # lvextend -L 600 /dev/vg00/lvol17
lvextend: Not enough free physical extents available.
Logical volume "/dev/vg00/lvol17" could not be extended.
Failure possibly caused by strict allocation policy

frardb03:/ # lvdisplay -v /dev/vg00/lvol17|more
--- Logical volumes ---
LV Name /dev/vg00/lvol17
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 500
Current LE 125
Allocated PE 250
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict

The VG has total 139 PE free.The two disks on which the lvols resides.One has 7PE free other has 132 PE free.

RGds

[Luk Vandenbussche]

Pls post vgdisplay -v vg00

[freddy_21]

hello marvik

Could i know how big your pe size.
check with vgdisplay vg00

if your pe size 4 MB and your free Pe 139 it's means 139*4MB=556MB

so you can create only 556MB.

thanks
freddy

[marvik]

Hi Luk,

frardb03:/ # vgdisplay vg00
--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 19
Open LV 19
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4350
VGDA 4
PE Size (Mbytes) 4
Total PE 8680
Alloc PE 8541
Free PE 139
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

[Luk Vandenbussche]

pls

vgdisplay -v vg00

[freddy_21]

correct. you can create lvol with 556 MB cant 600MB


thanks
freddy

[Raj D.]

Marvik,

check with
# vgdisplay -v vg00 | egrep '(dsk|Free)'


and then you can decide how much you can extend.


Cheers,
Raj.

[Adisuria Wangsadinata_1]

Hi Marvik,

You have unbalanced disk (one has 7 PE free & other has 132 PE free).

For mirror lvol, the good extend you can create is 7 PE free x 4 MBytes = 28 MBytes only. So the mirror can be 28 MBytes on one disk and 28 MBytes on the other.

If you want to have full extend with mirror, you can extend until 139 Free PE x 4 MBytes = 556 MBytes. And surely, some mirror will be on the same disk.

Hope this information can help you.

Cheers,
AW

[Piergiacomo Perini]

Hi marvik and all the guys,

i beg your pardon but i hope that you can do
"only" a

lvextend -L 276 /dev/vg00/lvol17

In fact , on vg00 there are 139 PE free.
So we have 69 PE free for lvol17 AND
69 PE free for mirror lv.
And 69*4M=276M.

hth
regards
pg

[Adisuria Wangsadinata_1]

Hi Marvik,

Agreed with PG, need to devide by 2 for mirror. So (139 Free PE x 4 MBytes) / 2 = 556 MBytes / 2 = 278 MBytes.

Cheers,
AW

[marvik]

Thanks for all ur replies but the problem remains.Its currently 500MB & if I increase to 500+278 thenit says .....

/dev/vg00/lvol17 512000 312809 186775 63% /db/FRARDB03/arch


frardb03:/ # lvextend -L 778 /dev/vg00/lvol17
Warning: rounding up logical volume size to extent boundary at size "780" MB.
lvextend: Not enough free physical extents available.
Logical volume "/dev/vg00/lvol17" could not be extended.
Failure possibly caused by strict allocation policy

[marvik]

Hi Luk,

Here is the vgdisplay -v output attached

[freddy_21]

lvol 19 ( 125 PE ) not have mirror. so that's the problem your mirror not balance.


thanks
freddy

[freddy_21]

please run this command

lvextend -m 1 /dev/vg00/lvol19 /dev/dsk/c1t15d0


remove lvol18 because the size 0
LV Name /dev/vg00/lvol18
LV Status available/syncd
LV Size (Mbytes) 0
Current LE 0
Allocated PE 0
Used PV 0

so i think you have 2 pe for each disk.

you cant add anymore.

Solution:
1. add pair disk with same size disk with existing ( 4340 PE)
2. add new disk at new volume group.
create another vg for your data.

thanks
freddy

[Piergiacomo Perini]

Hi again,

i hope no boring anyone but, in addition to Freddy solutions, other possible step are :

lvextend -L 28 /dev/vg00/lvol17

(so too many little space added _28 Mb_ but lvol are balanced and remain 125 PE free "unusable in balanced mode" on one disk)

or

lvextend -L 276 /dev/vg00/lvol17

(so 276 Mb are added but 'surely, some mirror will be on the same disk' as AW said ).

hth
regards

pg

[marvik]

Hi PP ,

lvextend -L 276 /dev/vg00/lvol17

this command will fail coz already FS is at 500 MB,though the first lvextend cmd holds true.
How do you find this " remain 125 PE free unusable in balanced mode" on one disk.

Cheers!

[Piergiacomo Perini]

Marvik you are extremely right ...
i have done a miscalculation ...
this is the right command

lvextend -l 132 /dev/vg00/lvol17

( with "-l" we take LE , so i hope to avoid
rounding )

but BEFORE try this one :

lvextend -l 194 /dev/vg00/lvol17

If return "usual" error the cause maybe strict policy.

sorry again

regards
pg

[Torsten.]

Please note your allocation policy is "Allocation strict". Maybe there are no free extends behind the LVOL.

[Piergiacomo Perini]

hi again Marvik, last note :
for me
lvextend -l 132 /dev/vg00/lvol17

is the only step possible .


lvextend -l 194 /dev/vg00/lvol17

should not return error (strict policy is not a problem) but is deprecable using mirror space.

hth
regards
pg

[Torsten.]

Sorry I mixed up strict and contiguous. Don't worry - it's friday.

[marvik]

Well I think the FS can only be increased by 28MB coz that the max size that can be mirrored as well on both the disks.

Thanks to all for all ur replies

Cheers!!
Marvik