Back-to-back power loss protection
The present disclosure generally relates to increasing data storage device lifetime by detecting synthetic PLP tests. Both upper and lower PLP time thresholds are set. When the PLP time is above the upper threshold, the data storage device is in a defensive PLP idle state. When the PLP time is between the upper and lower thresholds, the data storage device is in a defensive PLP detecting state. When the PLP time is below the lower threshold, the data storage device may enter the defensive PLP state if the number of times the PLP time is below the lower PLP time threshold either a consecutive number of times or a set number of times within a predefined window of time. While in the defensive PLP state, mounting is not completed and hence, a host device will not send any I/O commands and thus, not waste a PEC count.
1. A data storage device, comprising:
a controller configured to:
set an upper back-to-back (B2B) power loss prevention (PLP) time threshold;
set a lower B2B PLP time threshold;
enter a defensive PLP detecting mode when a B2B PLP time is between the upper B2B PLP time threshold and the lower B2B PLP time threshold, wherein during defensive PLP detecting mode the controller is configured to:
determine that PLP time is below the lower B2B PLP time threshold; and
track a number of consecutive times that the PLP time is below the lower B2B PLP time threshold with a lower threshold tracker; and
enter a defensive PLP mode when the number of consecutive times is equal to a predetermined number.
2. The data storage device of claim 1 , wherein the defensive PLP detecting mode is entered upon determining that the PLP time is below the upper B2B PLP time threshold.
3. The data storage device of claim 1 , wherein the controller is further configured to track a number of consecutive times the PLP time is below the upper B2B PLP time threshold.
4. The data storage device of claim 1 , wherein the controller is configured to reset the lower threshold tracker upon determining the PLP time is at or above the lower B2B PLP time threshold.
5. The data storage device of claim 1 , wherein the controller is configured to track a number of times the PLP time is below the upper B2B PLP time threshold with an upper threshold tracker.
6. The data storage device of claim 5 , wherein the controller is configured to reset the upper threshold tracker upon determining the PLP time is at or above the upper B2B PLP time threshold.
7. The data storage device of claim 6 , wherein the controller is configured to reset the lower threshold tracker upon determining the PLP time is at or above the upper B2B PLP time threshold.
8. The data storage device of claim 5 , wherein the controller is configured to enter a defensive idle mode upon determining the PLP time is at or above the upper B2B PLP time threshold.
9. The data storage device of claim 1 , wherein the controller is configured to reset the lower threshold tracker upon determining the PLP time is above the lower B2B PLP time threshold.
10. The data storage device of claim 1 , wherein the data storage device is a zone namespace (ZNS) device.
11. A data storage device, comprising:
a controller configured to:
set an upper back-to-back (B2B) power loss prevention (PLP) time threshold;
set a lower B2B PLP time threshold;
enter a defensive PLP detecting mode when a B2B PLP time is between the upper B2B PLP time threshold and the lower B2B PLP time threshold, wherein during the defensive PLP detecting mode the controller is configured to:
determine that the PLP time is below the lower B2B PLP time threshold; and
track a number of times that the PLP time is below the lower B2B PLP time threshold with a lower threshold tracker; and
enter a defensive PLP mode when the number of times is equal to a first number of times out of a second number of times, wherein the first number of times is less than the second number of times.
12. The data storage device of claim 11 , wherein the controller is configured to reset the lower threshold tracker upon determining the PLP time is at or above the upper B2B PLP time threshold.
13. The data storage device of claim 11 , wherein the first number is greater than half of the second number.
14. The data storage device of claim 11 , wherein the controller is configured to perform a mount process.
15. The data storage device of claim 14 , wherein the controller is configured to delay completing the mount process while in the defensive PLP mode.
16. The data storage device of claim 11 , wherein the data storage device is in a defensive PLP idle mode prior to entering the defensive PLP detecting mode.
17. The data storage device of claim 11 , wherein the data storage device is a zone namespace (ZNS) device, wherein the first number of times is 5 times, and wherein the second number of times is 9 times.
18. A data storage device, comprising:
a controller configured to:
detect entry into a synthetic power loss prevention (PLP) test;
track a PLP time;
compare the PLP time to a lower back-to-back (B2B) PLP time threshold and an upper B2B PLP time threshold;
switch between a defensive PLP idle state, a defensive PLP detecting state, and a defensive PLP state;
enter the defensive PLP detecting when a B2B PLP time is between the upper B2B PLP time threshold and the lower B2B PLP time threshold; and
withhold completion of a mount process while in the defensive PLP state.
19. The data storage device of claim 18 , wherein switching from the defensive PLP idle state to the defensive PLP detecting state occurs when the PLP time is below the upper B2B PLP time threshold.
20. The data storage device of claim 19 , wherein switching from the defensive PLP detecting state and the defensive PLP state occurs when the PLP time is below the lower B2B PLP time threshold.