Self-trimming of data stored in non-volatile memory using data storage controller
The present disclosure describes technologies and techniques for use with a data storage controller (such as a non-volatile memory (NVM) controller) to implement self-trimming of media data. In illustrative examples, an NVM controller stores a stream of video data in a NAND storage device, such as video obtained by a security camera. The controller also stores time stamps corresponding to portions of the video data. The controller then periodically (or during idle times) scans the stored information to identify video data that has exceeded a maximum data lifetime, such as data older than one week. Such data is deemed to be old/expired and is trimmed by the controller (by, e.g., marking corresponding entries in an allocation table as deleted or invalid). In this manner, the controller performs self-trimming of older video data to, for example, limit write amplification. NVMe examples are provided.
1. A method for use by a data storage controller for controlling a non-volatile memory (NVM) device, comprising:
storing a stream of data obtained over a period of time in the NVM device;
storing time-based parameters corresponding to portions of the stream of data;
subsequently scanning the NVM device in accordance with self-trim control parameters to identify portions of the stream of data stored within the NVM device that exceed a time-based threshold based on the corresponding time-based parameters, the self-trim control parameters indicating different operations depending on whether the data storage controller is idle or not; and
performing self-trim operations in accordance with the self-trim control parameters and based on whether the data storage controller is idle or not to selectively trim the portions of the stream of data within the NVM device that exceed the time-based threshold.
2. The method of claim 1 , wherein trimming the portions of the stream of data comprises marking the portions of the stream of data as one or more of deleted, invalid or unwritten in an allocation table, the allocation table within one or more of the data storage controller or the NVM device.
3. The method of claim 1 , wherein the time-based parameters comprise time stamps and wherein the time-based threshold comprises a maximum age threshold.
4. The method of claim 1 , further comprising:
obtaining the stream of data from a host device; and
generating the time-based parameters within the data storage controller.
5. The method of claim 1 , wherein the time-based parameters are stored in the NVM device along with corresponding streams of data within a same block of data, and wherein trimming the portions of the stream of data includes trimming an entire block of data in which the portions of the stream of data are stored.
6. The method of claim 1 , wherein the time-based parameters are stored separately from corresponding portions of the stream of data, and wherein the data storage controller maintains linking information relating the time-based parameters to the corresponding portions of the stream of data.
7. The method of claim 1 , wherein the portions of the stream of data that exceed the time-based threshold are trimmed even if the NVM device is not full.
8. The method of claim 1 , wherein the stream of data comprises one or more of video data and audio data.
9. The method of claim 1 , wherein the self-trim control parameters control the data storage controller to (a) scan the NVM device whenever the data storage controller is idle and (b) scan the NVM device periodically while the data storage controller is not idle.
10. The method of claim 9 , wherein the self-trim control parameters specify a frequency for scanning the NVM device while the data storage controller is not idle.
11. The method of claim 1 , further comprising selecting an amount of memory in the NVM device devoted to over-provisioning based on an amount of self-trimming performed, with the amount selected to reduce write amplification in the NVM device.
12. A data storage controller for controlling a non-volatile memory (NVM) device, comprising:
a data stream storage controller configured to store a stream of data obtained from a host device in the NVM device;
a time-based parameter storage controller configured to store time-based parameters corresponding to portions of the stream of data;
a data expiration controller configured to scan the NVM device in accordance with self-trim control parameters to identify portions of the stream of data stored within the NVM device that have expired, the self-trim control parameters indicating different operations depending on whether the data storage controller is idle or not; and
a trim controller configured to execute self-trim operations in accordance with the self-trim control parameters and based on whether the data storage controller is idle or not to selectively trim the portions of the stream of data within the NVM device that have expired.
13. The data storage controller of claim 12 , further comprising:
a time-based parameter generator configured to generate the time-based parameters.
14. The data storage controller of claim 13 , wherein the trim controller is configured to trim the portions of the stream of data that have expired by deallocating at least some portions of the stream of data from allocation tables associated with the NVM device, the allocation tables within one or more of the data storage controller or the NVM device.
15. The data storage controller of claim 12 , wherein the data storage controller further comprises a data linking controller configured to maintain information relating the time-based parameters to corresponding portions of the stream of data stored in the NVM device.
16. The data storage controller of claim 12 , wherein the host device is one or more of a vehicle video camera, a security camera, and an Internet of Things (IoT) device.
17. The data storage controller of claim 12 , wherein the self-trim control parameters are configured to control the data storage controller to (a) scan the NVM device whenever the data storage controller is idle and (b) scan the NVM device periodically while the data storage controller is not idle.
18. The data storage controller of claim 17 , wherein the self-trim control parameters are configured to specify a frequency for scanning the NVM device while the data storage controller is not idle.
19. The data storage controller of claim 12 , wherein the data stream storage controller is further configured to select an amount of memory in the NVM device devoted to over-provisioning based on an amount of self-trimming performed, with the amount selected to reduce write amplification in the NVM device.
20. A data storage system, comprising:
a non-volatile memory (NVM) device; and
a data storage controller having a processor configured to
store a stream of input data obtained from a host device in the NVM device,
store time-based parameters corresponding to portions of the stream of data,
scan the NVM device in accordance with self-trim control parameters to identify portions of the stream of data stored within the NVM device that are older than a maximum permissible age, the self-trim control parameters indicating different operations depending on whether the data storage controller is idle or not, and
perform self-trim operations in accordance with the self-trim control parameters and based on whether the data storage controller is idle or not to selectively trim the portions of the stream of data stored in the NVM device identified as older than the maximum permissible age.
21. The data storage system of claim 20 , wherein the self-trim control parameters are configured to control the data storage system (a) scan the NVM device whenever the data storage controller is idle and (b) scan the NVM device periodically while the data storage controller is not idle.
22. An apparatus for controlling a non-volatile memory (NVM) device, comprising:
means for storing an input stream of data in the NVM device, the means for storing being a component of a data storage controller;
means for storing data expiration parameters corresponding to portions of the input stream of data;
means for scanning the NVM device in accordance with self-trim control parameters to identify portions of the input stream of data stored within the NVM device that have expired based on the data expiration parameters, the self-trim control parameters indicating different operations depending on whether the data storage controller is idle or not; and
means for performing self-trim operations in accordance with the self-trim control parameters and based on whether the data storage controller is idle or not to selectively trim the portions of the stream of data stored in the NVM device that have expired.
23. The apparatus of claim 22 , further comprising:
means for generating the data expiration parameters as the input stream of data is obtained from a host device.
24. The apparatus of claim 23 , wherein the means for trimming includes means for logically deleting the portions of the stream of data from the NVM device.
25. The apparatus of claim 22 , wherein the self-trim control parameters are configured to control the means for scanning to (a) scan the NVM device whenever the data storage controller is idle and (b) scan the NVM device periodically while the data storage controller is not idle.