Article Number: 000144923
Internal Backup Power Supply
Each NAS controller is equipped with an internal backup power supply (BPS) that protects data during a power failure.
The BPS provides continuous power to the NAS controllers for a minimum of 5 minutes in case of a power failure and has sufficient battery power to allow the NAS controllers to safely shut down.
In addition, the BPS provides enough time for the NAS controllers to write all data from the cache to nonvolatile internal storage.
The NAS controllers regularly monitor the BPS battery status, which requires the BPS to maintain a minimum level of power for normal operation.
Data Caching and Redundancy
New and modified files are first written to the cache, and then cache data is immediately mirrored to the peer NAS controller (mirroring mode).
Data caching provides high performance, while cache mirroring between peer NAS controllers ensures data redundancy.
Cache data is ultimately transferred to permanent storage asynchronously through optimized data-placement schemes.
When cache mirroring is not possible, such as a single NAS controller failure or when the BPS battery status is low, NAS controllers write directly to storage (journaling mode)
Battery Calibration Cycle (Learn Cycle)
To ensure the BPS battery status is accurate, the NAS controllers routinely undergo battery calibration cycles.
During a battery calibration cycle, the BPS goes through charge and discharge cycles; therefore, battery error events during this process are expected.
A battery calibration cycle takes up to 7 days to complete.
If a NAS controller starts a battery calibration cycle, and the peer NAS controller BPS has failed, the NAS controllers enter journaling mode.
Entering this mode might impact performance, so you should repair a failed BPS as soon as possible.
Common Battery Events
Battery Calibration Cycle is in progress
A Battery Calibration Cycle in NAS Controller is in progress. The Battery Pack will go through charge and discharge cycles, therefore battery error events during this process are normal. This process may take up to 7 days from first notification to complete.
BPS on Controller is not operating properly - battery reports failed state (charge: 100%).
BPS on NAS Controller is not operating properly - battery reports failed state (charge: 100%). This could be the result of a recent calibration process - if you receive this event again after a few days for this specific controller, please contact Support.
Dell Compellent FS8600, EqualLogic FS7600, EqualLogic FS7610
21 Feb 2021