VG LUN Issue -Max 16 devices- can't extend VG

[MikeHS]

Hi all, I have two identical Linux systems.
2.4.21-32.ELhugemem
Red Hat Enterprise Linux AS release 3 (Taroon Update 5)
LVM version is lvm-1.0.8-14

Both systems have more then 16 LUN's presented from an EMC CX700 array. I created one VG and added 5 LUN's and then created another VG to use the rest. I have this error when I try to extend the VG past the 16th LUN.

vgextend vgeixpr01 /dev/emcpowerq1
vgextend -- INFO: maximum logical volume size is 2 Terabyte
vgextend -- ERROR: no physical volumes usable to extend volume group

I am using the emcpowerXX devices. Max LUN's is set for 256
options scsi_mod max_scsi_luns=256

Anyone have any ideas why this is happening. These are not in a cluster and have seperate LUN's but both more than 16. Thanks in advance

[Steven E. Protter]

Shalom,

The message seems to indicate that this is not a number of LUNS issue.

maximum logical volume size is 2 Terabyte

Size matters to distort a phrase.

fdisk -l, make sure you are using the correct disk in your vgextend command.

Also, if you are limited to 16 LUNS that could be because the vgcreate command was run with the -p 16 command.

As far as I know the vg will need to be created anew to get around this issue.

SEP

[MikeHS]

The LUN's are between 10-50GB in size and total for VG is around 400GB.

Vgcreate was used but not with -p 16 option

This occurs on two servers so I know it is the correct device. Same device /dev/emcpowerq on both systems fail.

fdisk -l shows valid information

[skt_skt]

do a "vgdisplay" and look for "Max PV" that should anser you.

In HP-UX if not specified the -p is set to 16. Not sure on linux.

[MikeHS]

One VG has 5 PV's. The other one is supposed to have 12 LUN's but at 11 it stops accepting vgextends and gives me the error in my initial post. MAX PV in the VG is set to 256. Thanks for the responses. All is helpful :-)

[Stuart Browne]

The other question to ask is what is the PE size?

From memory, RHEL3 uses LVM1, thus is fairly limited based on the PE size in use.

[skt_skt]

could u post?

1.LUN size of each disk used
2. vgdisplay -v