re: LVM on RP3440

[Gurcharan Sahota_2]

I am trying to setup a new volume group vg01 and am receiving the following error -

root@bduat:/dev/dsk> vgcreate -f /dev/vg01 /dev/dsk/c6t0d2
Increased the number of physical extents per physical volume to 35002.
vgcreate: Volume group "/dev/vg01" could not be created:
VGRA for the disk is too big for the specified parameters. Increase the
extent size or decrease max_PVs/max_LVs and try again.

I have run a pvcreate to create the disk, and created the group file. My question is, why am I getting this error and what does it mean.

root@bduat:/dev/dsk> ioscan -fnC disk
disk 6 0/4/1/0.100.0.0.0.0.2 sdisk CLAIMED DEVICE COMPAQ MS
A1000 VOLUME
/dev/dsk/c6t0d2 /dev/rdsk/c6t0d2

[TwoProc]

add the "-s" parameter to increase the size of each physical extent. The default is 4M. Try running it again with "-s 8 ", and if that doesn't work, then run it again with "-s 16".
vgcreate -s 8 -f /dev/vg01 /dev/dsk/c6t0d2.
As the man page for "vgcreate" says - be careful with the "-f" flag. You probably don't need it, and can leave it off.

[Mel Burslan]

when running vgcreate, assuming your are on version 11.11, the assumtion OS makes is max # of PEs per PV is 1016 and PE size is 16MBs. So according to this assumtions, largest single Disk/LUN you can have is about 16GBs. Obviouslyyour newly added disk is larger than this. See the man pages for vgcreate and concentrate on command line switches -s and -e. You have to adjust these values to accomodate the size of your new volume. Multiplication of the two values should be at least equal or larger than the size of your disk.

Hope this helps

[erics_1]

LVM is telling you that one of the default vg parameter needs to be changed to make the layout smaller. You can back off on the max pv default of 255 (ex. 100) or change the extent size to 8 which will probably get the vg created. See Knowledge Base doc id KBRC00009035 for more information on the error you're receiving.

Regards,
Eric

[erics_1]

I'll correct myself before someone else chimes in. Evidently, changing the max pv parameter will not help resolve your problem. Your best bet is increasing the PE size. No points on this please.

Regards,
Eric

[Steven E. Protter]

Try vgcreat with the -n option

-n number of physical volumes.

If you set that to a realistic number under 255 you get more units to spread on your disks.

SEP

[Devesh Pant_1]

I would suggest using the command
vgcreate -e number_of_extents -s pe_size
and the size of your disk is the multiple of
number_of_extents * pe_size(MB)

If the disk size is big enough go with a 16 or 32 MB of pe_size
thanks

Devesh

[Gurcharan Sahota_2]

just to add,

the OS is HPUX 11i

and the size of the disks in question are 146Gb.

[Devender Khatana]

Hi,

The error is coming because for large PV's/more than a few PV's in a VG, we need to alter PE SIze parameter to a higher value. The attached doc clarifies it.

HTH,
Devender

[Gurcharan Sahota_2]

thanks for all the responses, what I did was reduce the number of physical volumes for that volume group from 16 to 8, and kept the size of the PEs to 4. The lvcreates then worked for the LVs that I needed to create.

[Senthil Kumar .A_1]

Hi Gurcharan,


vgcreate -s 16 /dev/vg01 /dev/dsk/c6t0d2

will work for you.. it will create vg01 with 16MB PE size.


Regards.

[Venkatesan_5]

Hi Gurcharan,

The same problem has been faced by me...you can try this

# mkdir /dev/vg01
# mknod /dev/vg01/group c 64 0x010000
# pvcreate -f /dev/rdsk/c6t0d2
Physical volume "/dev/rdsk/c6t0d2" has been
successfully created.
# vgcreate -s 32 /dev/vg01 /dev/dsk/c3t2d0
the (-s) option will change the PE Size to 32 and now it will create the vg.
note: if you are adding another disk and extending the vg, no need to give -s option.
just give...
#vgextend /dev/vg01 /dev/dsk/c3t3d0.

hope this should solve your problem...eventhough try for installing the patch also...


regds,

Venkatesan.