HP XP7 Storage - Manual (Page 30)

SDM; the default threshold is 0x500.When Level 1 Sleep is set to Disable, write I/Os to
volumes are not put in a wait status.
•
Level 1: This level of control is performed when the sidefile capacity is equal to or larger than
the level-1 threshold, and is smaller than the level-2 threshold.
Write I/Os to volumes are put in a wait status by command retry when the sleep wait threshold
(that is, level-1 threshold) is exceeded.
•
Level 2: This level of control is performed when the sidefile capacity is equal to or larger than
the level-2 threshold, and is smaller than the level-3 threshold.
Write I/Os to volumes are put in a wait status by SCP-SCI reporting when the SCP-SCI reporting
threshold (that is, level-2 threshold) is exceeded.
•
Level 3: This level of control is performed when the sidefile capacity is equal to or larger than
the level-3 threshold.
Sidefile puncture will occur.
The following figure shows levels of controlling write data when the Donot Block option is disabled.
30 Controlling the amount of write data