VERITAS Storage Foundation 4.1 Intelligent Storage Provisioning Administrator's Guide

Determining the Maximum Volume Size
46 VERITAS Storage Foundation ISP Administrator’s Guide
Each invocation of vxvoladm is applied to only a single storage pool that has been configured
within a disk group. The default disk group is that aliased by the setting of defaultdg. You can
specify an alternate disk group by using the -g diskgroup option.
Note Refer to the vxvoladm(1M) manual page for full details on using the vxvoladm
command.
Setting Default Values for vxvoladm
You can define default values for vxvoladm in the file /etc/default/allocator, or in an
alternate defaults file that you specify using the -d option. The defaults listed in this file are used
unless they are overridden by a value specified on the command line. If a value is not defined in a
defaults file or on the command line, vxvoladm uses a built-in default value.
Tip The file, /etc/default/allocator_readme, contains a copy of the defaults file as
it is shipped and first installed.
By default, the attribute settings in the installed /etc/default/allocator file are
commented out. If required, you can uncomment the entries, and edit their values. If you do this,
you should first make a backup copy of the original unedited file to keep for reference.
The following entry for default_rules in the /etc/default/allocator file is
commented out by default:
# default_rules=desired confineto "ProductId"
If enabled, this rule changes the default behavior of ISP so that it attempts to confine volumes to
disks with the same product ID. The rule may also prevent hot-relocation or volume transformation
taking place if disks with the same product ID are not available.
For a single invocation of the vxvoladm command, you can override the default values of
attributes that are defined in the /etc/default/allocator file, or that are built into
vxvoladm, by specifying them as comma-separated arguments to the -o option.
Determining the Maximum Volume Size
Before creating a volume, you may wish to check whether there is sufficient storage available. You
can use the following command to determine the maximum size of a volume with a given
capability that you can create in the data storage pool of a disk group:
# vxvoladm [-g diskgroup] [-p storage_pool] [-b] maxsize \
[storage_specification] [attribute=value ...]
Specify the -b option if you want to run this command in the background. Otherwise, it will block
until it has completed its calculation of the maximum volume size.