Storage > LUNs : Understanding LUNs : Guidelines for creating LUNs
Guidelines for creating LUNs
System Manager
includes several features that help you to create, edit, or delete LUNs, and to manage Snapshot copies for a selected LUN.
LUNs interact with Windows hosts and with storage systems in different ways. The basic sequence for provisioning storage is to create the LUNs, create the initiator groups, and map the LUNs to the initiator groups. After you create your LUNs, you can manage them in several ways. For example, you can control LUN availability, unmap a LUN from an initiator group, and rename or delete a LUN. Use the following guidelines when creating a LUN.
The LUN name must start with a letter or an underscore (“_”) if you choose to automatically create a volume. The designated volume name is truncated to 249 characters if the LUN name is longer than 249 characters. Any hyphen (“-”), left brace (“{”), right brace (“}”), and period (“.”) in the LUN name is replaced with an underscore in the volume name.
The LUN description is an optional attribute that you can use to specify additional information about the LUN.
The usable space in the LUN depends on host or application requirements for overhead. For example, partition tables and metadata on the host file system reduce the usable space for applications. In general, when you format and partition LUNs as a disk on a host, the actual usable space on the disk depends on the overhead required by the host.
The disk geometry used by the operating system determines the minimum and maximum size values of LUNs. For information about the maximum sizes for LUNs and disk geometry, see the vendor documentation for your host OS. If you are using third-party volume management software on your host, consult the vendor’s documentation for more information about how disk geometry affects LUN size.
