Which operational state of an XtremIO X2 NVRAM card will trigger SuperCap discharging?

The SuperCapacitor (SuperCap) on an XtremIO X2 NVRAM card is a critical component of the data protection mechanism. Its primary function is to provide temporary power to the Storage Controller in the event of an unexpected loss of main AC power. When a power failure is detected, the SuperCap immediately begins to discharge, supplying the necessary energy for the system to perform a "vaulting" operation. This process involves writing all data from the volatile DRAM write cache to the non-volatile SSDs, ensuring data integrity and preventing data loss.

B. Normal Operation: During normal operation, the SuperCap is either fully charged and in a standby state or is actively charging; it does not discharge.
C. Data Secured: This state is the result of the SuperCap discharging and the subsequent successful vaulting of data. It is not the trigger for the discharge.
D. Power Restored: When main power is restored, the SuperCap begins to recharge to prepare for any future power loss events. It does not discharge.

1. Dell EMC XtremIO Storage Array X2 Architecture, A Detailed Review (White Paper H16274.4, April 2019):

Page 12, Section: Data protection: "In the event of a power failure to a Storage Controller, the contents of the write cache are vaulted to the SSDs. This process is powered by supercapacitors, which provide enough power to the Storage Controller to complete the vaulting process." This statement directly links a "power failure" to the activation of the supercapacitors.

2. Dell EMC XtremIO X2 Hardware Installation and Upgrade Guide (Docu91279, Revision 07, March 2019):

Page 17, Table 4, Storage Controller (rear view) components: Item 10 describes the "NVRAM card with two super-capacitors." The guide establishes that this hardware is the power backup mechanism, which is inherently designed to function upon power loss. The entire purpose of the component is for power-fail scenarios.