Veritas: Private area lengthΒΆ

Title:Veritas: Private area length
Author:Douglas O’Leary <dkoleary@olearycomputers.com>
Description:Veritas: Private area length
Date created:08/2008
Date updated:09/2009
Disclaimer:Standard: Use the information that follows at your own risk. If you screw up a system, don’t blame it on me...

Systems that have a very large disk group configurations can eventually exhaust the private region size in the disk group, which results in not being able to add more configuration objects, like volumes, disks, plexes, or subdisks.

There are two options:

  1. Make the private area larger.
  2. Create a new disk group in which to put the new disks & volumes.

To set the private area length to a certain size in 512 byte blocks, execute:

vxdisksetup -i c#t#d# privlen=######

To determine how much of the private region you’re currently using, execute:

vxdg list ${group} | grep permlen
config:    seqno=0.3676 permlen=1090 free=1079 templen=7 loglen=165

To increase the private region, you must increase it on all the disks in the disk group. The process is as follows:

  1. Complete backup of all data in disk group
  2. Complete removal of all disks
  3. Reinitalizing with new private area length
  4. Remake the disk group and volumes
  5. Restore

The private area must be increased on all disks in the disk group as the system will use the smallest one as the size of the permlen area. If you later add a disk with a smaller private area, you’re risking data access problems. SUN’s not sure what would happen, but nobody thinks it’d be pretty.

Addendum: Gene Trantham wrote a great article called VxVM Private Regions: Mechanics & Internals of the VxVM Configuration Database in SUN’s Blueprints. Part of that article discusses this exact issue and comes up with a way around it without blowing away the whole disk group.