2. USAGE GUIDELINES › 2.1 TLM Component Usage Guidelines › 2.1.4 TLM Capacity Planning

2.1.4 TLM Capacity Planning

Capacity planning for tape library management systems is
essential to ensure that acceptable levels of performance are
sustained over time.  The TLM component database files are
useful for observing key metric value trends over time.

The Tape Volume (TMCTMV) file is ideal for trending media
usage and total library capacity.  Most data centers have a
variety of different tape cartridge media types.
Additionally, most data centers use virtual tape subsystems
as well as traditional tape.


It is a best practice to use the Volume Group (VOLGROUP) data
element to assign unique values to tape volumes with
different characteristics.  If adopted, this practice
supports useful analysis of the TLM component TMCTMV file at
summarized timespans.

Assigning values to the VOLGROUP data element is described in
section 7.1.3.2, TLM VOLGROUP Derivation Routine (VOLGPRTE).
VOLGROUP is a summarization key in both the tape data set and
tape volume files.  For capacity planning, it is important to
use the VOLGPRTE routine to assign unique VOLGROUP data
element values that identify virtual tape volumes, and
additional unique values for each physical tape cartridge
media type.

When implemented, this best practice ensures that the TMCTMV
file will maintain data granularity levels at summarized
timespans sufficient to provide tape media usage and
availability information suitable for capacity planning.