LVM and VxVM

max numbers of logical volumes in a volume group

 
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Ernesto Rincon
Frequent Advisor

max numbers of logical volumes in a volume group

Hi everybody:

Someone knows if is possible to create more than 255 logical volumes in a volume group?

I hope someone can help me.

Regards!!
5 REPLIES 5
Isralyn Manalac_1
Regular Advisor

Re: max numbers of logical volumes in a volume group

Yes, you can. The default is 255 but you can change the max LV using the -l option in the vgcreate command.

Regards,

Isralyn
Joseph Loo
Honored Contributor
Solution

Re: max numbers of logical volumes in a volume group

hi,

that is not possible, read this:

http://www1.itrc.hp.com/service/iv/node.do?source=search&node=prodITRC/WW_Start/N1|20|3|1|4|2

the -l option in vgcreate only allows value from 1 to 255.

for easier maintenance, grouping LVs into separate VGs would be a better option.

regards.
what you do not see does not mean you should not believe
Devender Khatana
Honored Contributor

Re: max numbers of logical volumes in a volume group

Hi,

Please find enclosed file which explains the limitations on almost all of LVM parameters. Yes, it is obvious then you can group multiple logical volumes in seperate volume groups for convenience in maintenance and should never go as high as maximum limit. Also do not forget to chnage PE Size as per other parameters in your VG. This also is described here.

HTH,
Devender
Impossible itself mentions "I m possible"
Nguyen Anh Tien
Honored Contributor

Re: max numbers of logical volumes in a volume group

NO 255 is limit, But I never try to create more than 255 ( It is many for my system).

If you want to create n lv in one vg, command is
vgcreate(1M) -l n vgname pv1 pv2 ...

HP is simple
Devender Khatana
Honored Contributor

Re: max numbers of logical volumes in a volume group

Hi,

I could not understand your query properly. It seems you are trying to create a LV in a new vg. Then the steps for this inludes -

1. First identify spare Physical Volumes.
2. pvcreate /dev/rdsk/cxtydz (Optional -f if required to force)
3. Vgcreate includes -
i) mkdir /dev/vg0X
ii) mknod /dev/vg0X/group 64 0*0x0000 ( This x should be unique in system, confirm by "ll /dev/vg*/group" and see minor number.)
iii) Now execute vgcreate command. And do not forget to changes urgent parameters like PE_SIZE,MAX_LV,MAX_PV etc. depending upon your requirements. See man vgcreate for details.These can be specified only initially and can not be changed later.
iv) Create Logical volume in vg using lvcreate command ( Man lvcreate for details)
v) Create file system on that LV.
vi) Create mount point directory and make entry in /etc/fstab for automount on boot. and mount it now manually.

Note- All this can be easily done through SAM also if you are not confident on command level.

HTH,
Devender
Impossible itself mentions "I m possible"