topic Re: problem extending l-volume in Operating System - HP-UX

problem extending l-volume

Mauro Gatti — Tue, 11 Feb 2003 12:47:43 GMT

I've a problem tring to extend a logical volume:

virgo# lvextend -L 1500 /dev/vg00/lvol5
Warning: rounding up logical volume size to extent boundary at size "1504" MB.
lvextend: Not enough free physical extents available.
Logical volume "/dev/vg00/lvol5" could not be extended.
Failure possibly caused by strict allocation policy

On vg00 seems to be sufficient space...
virgo# vgdisplay vg00
--- Volume groups ---
VG Name /dev/vg00
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 12
Open LV 12
Max PV 16
Cur PV 2
Act PV 2
Max PE per PV 4350
VGDA 4
PE Size (Mbytes) 8
Total PE 8680
Alloc PE 7521
Free PE 1159
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

But I've seen that lvol5 is mirrored on:

virgo# lvdisplay -v /dev/vg00/lvol5
--- Logical volumes ---
LV Name /dev/vg00/lvol5
VG Name /dev/vg00
LV Permission read/write
LV Status available/syncd
Mirror copies 1
Consistency Recovery MWC
Schedule parallel
LV Size (Mbytes) 1024
Current LE 128
Allocated PE 256
Stripes 0
Stripe Size (Kbytes) 0
Bad block on
Allocation strict
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c1t6d0 128 128
/dev/dsk/c2t6d0 128 128

Maybe the problem is that there isn't more space on both PV so I can't allocate same PV on both disk?

--- Physical volumes ---
PV Name /dev/dsk/c1t6d0
PV Status available
Total PE 4340
Free PE 0
Autoswitch On

PV Name /dev/dsk/c2t6d0
PV Status available
Total PE 4340
Free PE 1159
Autoswitch On

Can I extend lvol5 adding a new PV on vg00?

Thank You

Re: problem extending l-volume

Armin Feller — Tue, 11 Feb 2003 12:52:34 GMT

If the lvol is mirrored, you have to devide the "Free PE 1159" by number of mirror copies and that is the max PE range you are able to extend the lvol. Further you need enought free space on different disks, because the allocation is set to 'strict' you are not able to mirror to the same disk.

Re: problem extending l-volume

James R. Ferguson — Tue, 11 Feb 2003 13:11:48 GMT

Hi:

Strict allocation enforces the requirement that keep mirror extents are kept only on separate physical volumes.

Your problem is that /dev/dsk/c1t6d0 has no more free physical extents.

One approach would be to unmirror lvol5 from /dev/dsk/c1t6d0; 'vgextend' in a new physical volume; 'lvextend' lvol5 on /dev/dsk/c2t6d0; and then (re)mirror lvol5 onto the *new* physical volume.

Regards!

...JRF...

Re: problem extending l-volume

Rita C Workman — Tue, 11 Feb 2003 13:28:40 GMT

I was wondering when you did the lvextend if you specified the disk?

I have found when increasing lvol on vg00 to NOT include the specific disk, especially if it is mirrored.

e.g.
lvextend -L 1500 /dev/vg00/lvol5

Just a thought,
Rita

Re: problem extending l-volume

Jakes Louw_1 — Wed, 12 Feb 2003 13:22:19 GMT

Rita, be careful if you do that, as you can end up with parts of your mirror on the wrong set of disks.
Ie: if your vg00 consists of /dev/dsk/c0t2d0, c0t3d0, c0t4d0 on one SCSI, and c1t2d0, c1t3d0, and c1t3d0 on the other SCSI in the cabinet, you could end up mirroring the data onto a disk on the same SCSI card, which is bad practice.