The Instant Capacity software tracks the expected
number of inactive components (cores, cells, and memory) in a complex
and knows the actual number of active and inactive components. The
complex is in compliance if the actual number of inactive components
meets or exceeds the expected number of inactive components.
The complex is out of compliance if the actual
number of inactive components is less than the expected number of
inactive components and no temporary capacity exists.
However, a complex can also get out of compliance
if a cell is removed from the complex. For example, if a cell contains
inactive cores that are contributing to compliance, and the cell is
removed, there will be fewer inactive cores on the complex. This may
result in the complex being out of compliance and temporary capacity
may begin to be debited.
Example A-1 Removing a Cell and Decreasing the Actual Number of Inactive
Cores
For example, a complex contains two cells, with
two partitions having two inactive and two active cores each. The
Instant Capacity software expects the complex to have four inactive
cores. If one of the cells (0) experiences a hardware problem, and
you remove the cell, the complex is left with only one cell that contains
two active and two inactive cores. The complex is now out of compliance
because four inactive cores are expected to be in the complex, yet
there are only two inactive cores.
Table A-1 Removing a Cell — Decrease Inactive Cores
State | Partition (Cell)
0 | Partition (Cell)
1 | Notes |
|---|
Before Cell 0 is Removed | 2 active, 2 inactive | 2 active, 2 inactive | 4 inactive cores expected (in compliance) |
After Cell 0 is Removed | 0 active, 0 inactive | 2 active, 2 inactive | 4 inactive cores expected (out of compliance) |
In the above example, all cores in the removed
cell are assumed to be active. This causes the complex to be out of
compliance as the complex has two more active cores than it has core
usage rights. This results in the complex consuming two hours of temporary
capacity for each hour that the complex remains in this state. Deactivating
another core from Cell 1 decreases the amount of temporary capacity
being consumed, but since at least one core must be active per active
cell, this complex cannot remain in compliance except through the
use of temporary capacity.
Note that removal of a cell, followed by a reboot
of the affected partition, does not affect the intended active number
for the partition, or the required number of inactive cores which
is determined by the overall availability of core usage rights across
the complex. During the period when the cell is absent, temporary
capacity may be consumed if the number of inactive cores is less than
the expected number of inactive cores. Having additional Temporary
Instant Capacity allows this system to remain in compliance even in
the presence of a cell hardware failure.
Printable version
