Battery operation for Storwize V7000 Gen2 control enclosures
Each node canister in the control enclosure caches critical data and holds state information in volatile memory.
The battery is maintained in a fully charged state by the battery subsystem. At maximum power, the battery can save critical data and state information in two back-to-back power failures. If power to a node canister is lost, saving critical data starts after a five-second wait. (If the outage is shorter than five seconds, the battery continues to support the node and critical data is not saved.) The node canister stops handling I/O requests from host applications. The saving of critical data runs to completion, even if power is restored during this time. The loss of power might be because the input power to the enclosure is lost, or because the node canister is removed from the enclosure.
When power is restored to the node canister, the system restarts without operator intervention. How quickly it restarts depends on whether there is a history of previous power failures. The system restarts only when the battery has sufficient charge for the node canister to save the cache and state data again. A node canister with multiple power failures might not have sufficient charge to save critical data. In such a case, the system starts in service state and waits to start I/O operations until the battery has sufficient charge.
- Status LED - Green
- Fault LED - Amber
Design parameters
- The design life of the battery in the Storwize V7000 Gen2 is five years service after one year on the shelf.
- Each battery is automatically reconditioned every three months to measure the battery capacity. Batteries in the same enclosure are not reconditioned within two days of each other. If a battery has a lower capacity than required (below the planned threshold), it is marked as "End Of Life" and should be replaced.
- Each battery provides power only for the canister in which it is installed. If a battery fails, the canister goes offline and reports a node error. The single running canister destages its cache and runs the I/O group in "write-through" mode until its partner canister is repaired and online.