Use this page to view the distribution of data on physical
volumes marked full on a IBM® TS7700 Cluster.
The distribution can be used to select an appropriate reclaim threshold.
The Active Data Distribution page displays the percent utilization
of physical volumes in increments of 10%.
- Number of Full Volumes at Utilization Percentages
- This table shows the number of physical volumes marked as full
in each physical volume pool, according to percentage of volume used.
Fields displayed include:
- Pool
- The physical volume pool number. This number is a hyperlink; click
it to display a graphic representation of the number of physical volumes
per utilization increment in a given pool.
- When you click the pool number hyperlink, the Active Data Distribution sub
page opens. This sub page contains the following fields and information:
- Pool
- To view graphical information for another pool, select the target
pool from this drop down menu.
- Current Reclaim
Threshold
- The percentage used to determine when to perform reclamation of free
storage on a stacked volume. When the amount of active data on a physical stacked volume drops below
this percentage, a reclaim operation is performed on the stacked volume.
Physical volumes hold
between the threshold value and 100% of data. Setting the threshold too low results in more physical
volumes being needed; setting the threshold too high might affect the ability of the TS7700 Tape Attach to perform host
workload because it is using its resources to perform reclamation. Experiment to find a threshold
that matches your needs.
The valid range of possible values is 0-95(%) and can be entered in
1% increments; 35% is the default value. If the system is in a heterogeneous tape drive environment,
then this threshold is for R/W media.
- This percentage is a hyperlink; click it to open the Modify
Pool Properties page, where you can modify the percentage used
for this threshold.
- Number of Volumes with Active Data
- The number of physical volumes that contain active data.
- Pool n Active Data Distribution
- This graph displays the number of volumes that contain active
data per volume utilization increment for the selected pool. On this
graph, utilization increments (x axis) do not overlap.
- Pool n Active Data Distribution (cumulative)
- This graph displays the cumulative number of volumes that contain
active data per volume utilization increment for the selected pool.
On this graph, utilization increments (x axis) overlap, accumulating
as they increase.
- The Active Data Distribution sub page also displays utilization
percentages for the selected pool, excerpted from the Number of
Full Volumes at Utilization Percentages table.
- Media Type
- The type of cartridges contained in the physical volume pool.
If more than one media type exists in the pool, each type is displayed,
separated by commas. Possible values are:
- Any 3592
- Any media with a 3592 format.
- JA
- Enterprise Tape Cartridge (ETC)
- JB
- Extended Data Enterprise Tape Cartridge (EDETC)
- JC
- Enterprise Advanced Data Cartridge (EADC)
- JD
- Advanced Type D Data (ATDD)
- JE
- Advanced Data E Cartridge (ATED)
- JJ
- Enterprise Economy Tape Cartridge (EETC)
- JK
- Enterprise Advanced Economy Tape Cartridge (EAETC)
- JL
- Advanced Type L Economy (ATLE)
- JM
- Advanced Type E Economy Cartridge (ATME)
- Percentage of Volume Used (0+, 10+, 20+ ...)
- Each of the last 10 columns in the table represent a 10% increment
of total physical volume space used. For instance, the column heading 20+ represents
the 20–29% range of a physical volume used. For each pool, listed
is the total number of physical volumes that occur in each range.
For information about the steps you can take to achieve peak network performance,
refer to
IBM TS7700
Series Best Practices -
Understanding, Monitoring and Tuning the TS7700 Performance, WP101465, available from the
TechDocs link in the Related information
section.