System and method for performing data retention that incorporates environmental conditions
View Patent ↗A solid-state storage system is described with a method for adjusting the frequency of data retention operations. The data retention operation frequency can be increased or decreased according to a variety of environmental factors such as error code frequency, system temperature, altitude, and other operating conditions. These factors can indicate an increased or decreased risk of failure and accordingly provide increased or decreased rates of data retention operations.
1. A method of data retention in a storage system, comprising:
storing data in a solid-state storage array of the storage system in response to commands received by the storage system from a host system, the solid-state storage array susceptible to data loss in the absence of periodic data relocation;
receiving or determining parameters indicative of a risk of data loss;
dynamically determining a data relocation rate, the determining comprising adjusting a manufacturer's recommended relocation rate based at least in part on the parameters indicative of the risk of data loss; and
relocating the data on the solid-state storage array at the determined data relocation rate,
wherein the method is performed by a controller of the storage system.
2. The method of claim 1 , wherein the parameters include at least one of an error code rate, a temperature of the storage system, an operating altitude, and a number of data accesses to the storage array.
3. The method of claim 1 , wherein the manufacturer's recommended rate comprises a data retention frequency curve.
4. The method of claim 1 , wherein the dynamically determined data relocation rate is higher than the manufacturer's recommended rate when the parameters indicative of a risk of data loss indicate a higher risk of data loss.
5. The method of claim 1 wherein the dynamically determined data relocation rate is lower than the manufacturer's recommended rate when the parameters indicative of a risk of data loss indicate a lower risk of data loss.
6. A non-volatile storage system, comprising:
a solid-state memory array configured to store data, the solid-state memory array susceptible to long-term storage data loss; and
a controller configured to mitigate long-term data loss in the solid-state memory array by periodically relocating data in the solid-state memory array;
the controller further configured to:
receive or determine data indicative of a likelihood of data loss of the solid-state memory array;
process the data indicative of the likelihood of data loss to determine a maintenance factor;
adjust a manufacturer's recommended maintenance period based at least partly on the maintenance factor to determine a maintenance period; and
periodically relocate data in the solid-state memory array at a rate which depends upon the maintenance period.
7. The storage system of claim 6 , wherein the controller is further configured to periodically receive data indicative of a likelihood of data loss, process the data indicative of the likelihood of data loss to determine the maintenance factor, and adjust the manufacturer's recommended maintenance period based at least partly on the maintenance factor to determine the maintenance period.
8. The storage system of claim 6 , wherein the data indicative of a likelihood of data loss comprises at least one of an error rate, a temperature, an operational altitude, and a usage frequency.
9. The storage system of claim 8 , wherein the error rate is obtained from read operations performed by the controller on data stored in the solid-state memory array, the read operations being performed in response to a command from a host system.
10. The storage system of claim 8 , wherein the error rate is obtained from periodic read operations performed by the controller on data stored in the solid-state memory array, the periodic read operations not being performed in response to a command from a host system.
11. A method for reducing data loss in a storage system, the method comprising:
storing data in a plurality of storage elements in a solid-state storage array;
receiving data related to operational conditions indicative of a risk of data loss;
dynamically determining a data relocation rate, the determining comprising adjusting a manufacturer's recommended relocation rate based at least in part on the data related to operational conditions indicative of the risk of data loss; and
for one or more of the plurality of storage elements,
periodically relocating, at the determined data relocation rate, the data stored in the one or more storage elements,
wherein relocation of the data at least partly mitigates a risk of data loss due to the data being stored in the solid-state storage array for an extended time period.
12. The method of claim 11 , wherein the frequency at which the determining and relocating are performed is determined at least in part by the operational conditions indicative of a risk of data loss.
13. The method of claim 11 , wherein each of the storage elements is a block.
14. The method of claim 11 , wherein the operational conditions comprise at least one of an error code quantity, a temperature of the storage system, an operating altitude, and a number of data accesses to the storage array.
15. The method of claim 1 , further comprising:
dynamically determining a plurality of data relocation rates corresponding to a plurality of data sets stored in the solid-state storage array; and
relocating each of the plurality of data sets at the corresponding data relocation rate.
16. The method of claim 1 , wherein dynamically determining the data relocation rate further comprises adjusting the manufacturer's recommended relocation rate based at least in part on the parameters indicative of the risk of data loss and on a relative importance of the stored data.
17. The storage system of claim 6 , wherein the controller is further configured to:
determine a plurality of maintenance periods corresponding to a plurality of data sets stored in the solid-state memory array; and
periodically relocate each of the plurality of data sets in the solid-state memory array at a rate which depends on the corresponding maintenance period.
18. The storage system of claim 6 , wherein the controller is further configured to determine the maintenance period based at least partly on the adjusted manufacturer's recommended maintenance period and on a relative importance of the stored data.
19. The method of claim 11 , further comprising:
dynamically determining a plurality of data relocation rates corresponding to a plurality of data sets stored in the solid-state storage array; and
periodically relocating each of the plurality of data sets at the corresponding data relocation rate.
20. The method of claim 11 , wherein dynamically determining the data relocation rate further comprises adjusting the manufacturer's recommended relocation rate based at least in part on the data related to operational conditions indicative of the risk of data loss and on a relative importance of the stored data.