Method, device, and computer program product for managing address mapping in storage system

1. A method for managing an address mapping of a storage system, a group of data objects in the storage system being mapped to a group of buckets in the address mapping, the group of buckets being divided into a first group of active shards that are associated with a group of storage devices in the storage system, respectively, the method comprising:

receiving a first write request for writing a first data object to the storage system;

adjusting a shard count of active shards in the first group of active shards based on an access load of the storage system and a load threshold condition of the storage system, wherein the load threshold condition comprises an upper threshold, and the adjusting the shard count of active shards in the first group of active shards comprises increasing the shard count in response to determining that the access load of the storage system is higher than a lower threshold less than the upper threshold;

updating the address mapping so as to map the first data object to a first bucket in the group of buckets, resulting in an updated address mapping;

instructing the storage system to store the first data object to a first storage device in the group of storage devices, the first storage device being associated with a first active shard to which the first bucket belongs; and

managing the storage system based on the updated address mapping.

2. The method of claim 1 , wherein the managing the storage system based on the updated address mapping comprises: in response to determining a state of the storage system meeting a predetermined regeneration condition,

identifying the first group of active shards as a first group of inactive shards; and

dividing the group of buckets into a second group of active shards.

3. The method of claim 2 , wherein the predetermined regeneration condition comprises a threshold count of data objects associated with a shard, and the method further comprises:

regarding a given active shard in the first group of active shards, determining an object count of data objects associated with the given active shard; and

dividing the group of buckets into the second group of active shards in response to determining the object count is higher than the threshold count.

4. The method of claim 1 , wherein the load threshold condition comprises the lower threshold, and the adjusting the shard count of active shards in the first group of active shards comprises:

decreasing the shard count in response to determining the access load of the storage system is lower than the lower threshold.

5. The method of claim 1 , wherein the managing the storage system based on the updated address mapping comprises:

determining data distribution of a plurality of data objects in the first group of active shards; and

merging successive active shards in the first group of active shards based on the data distribution.

6. The method of claim 2 , wherein the managing the storage system based on the updated address mapping comprises:

receiving a second write request for writing a second data object to the storage system;

updating the address mapping so as to map the second data object to a second bucket in the group of buckets; and

instructing the storage system to store the second data object to a second storage device in the group of storage devices, the second storage device being associated with a second active shard to which the second bucket belongs.

7. The method of claim 1 , wherein the managing the storage system based on the updated address mapping comprises:

determining a first generation identifier and a first shard identifier of the first active shard associated with the first data object based on the group of active shards; and

adding to the address mapping a first association between the first data object and the first active shard, the first active shard being represented using the first generation identifier and the first shard identifier.

8. The method of claim 7 , wherein the managing the storage system based on the updated address mapping comprises:

receiving a read request for reading a target data object from the storage system;

determining a target shard associated with the target data object based on associations included in the address mapping; and

reading the target data object from the storage system based on the target shard.

9. A device for managing an address mapping of a storage system, a group of data objects in the storage system being mapped to a group of buckets in the address mapping, the group of buckets being divided into a first group of active shards which are associated with a group of storage devices in the storage system, respectively, the device comprising:

at least one processor;

a volatile memory; and

a memory coupled to the at least one processor and having instructions stored thereon, the instructions, when executed by the at least one processor, causing the device to perform acts comprising:

receiving a first write request for writing a first data object to the storage system;

adjusting a shard count of active shards in the first group of active shards based on an access load of the storage system and a load threshold condition of the storage system, wherein the load threshold condition comprises an upper threshold, and the adjusting the shard count of active shards in the first group of active shards comprises increasing the shard count in response to determining that the access load of the storage system is higher than a lower threshold;

updating the address mapping so as to map the first data object to a first bucket in the group of buckets, resulting in an updated address mapping;

instructing the storage system to store the first data object to a first storage device in the group of storage devices, the first storage device being associated with a first active shard to which the first bucket belongs; and

managing the storage system based on the updated address mapping.

10. The device of claim 9 , wherein the managing the storage system based on the updated address mapping comprises: in response to determining a state of the storage system meeting a predetermined regeneration condition,

identifying the first group of active shards as a first group of inactive shards; and

dividing the group of buckets into a second group of active shards.

11. The device of claim 10 , wherein the predetermined regeneration condition comprises a threshold count of data objects associated with a shard, and the acts further comprise:

regarding a given active shard in the first group of active shards, determining an object count of data objects associated with the given active shard; and

dividing the group of buckets into a second group of active shards in response to determining the object count is higher than the threshold count.

12. The device of claim 9 , wherein the load threshold condition comprises the lower threshold, and the adjusting the shard count of active shards in the first group of active shards comprises:

decreasing the shard count in response to determining the access load of the storage system is lower than the lower threshold.

13. The device of claim 9 , wherein the managing the storage system based on the updated address mapping comprises:

determining a data distribution of a plurality of data objects in the first group of active shards; and

merging successive active shards in the first group of active shards based on the data distribution.

14. The device of claim 10 , wherein the managing the storage system based on the updated address mapping comprises:

receiving a second write request for writing a second data object to the storage system;

updating the address mapping so as to map the second data object to a second bucket in the group of buckets; and

instructing the storage system to store the second data object to a second storage device in the group of storage devices, the second storage device being associated with a second active shard to which the second bucket belongs.

15. The device of claim 9 , wherein the managing the storage system based on the updated address mapping comprises:

determining a first generation identifier and a first shard identifier of the first active shard associated with the first data object based on the group of active shards; and

adding to the address mapping a first association between the first data object and the first active shard, the first active shard being represented using the first generation identifier and the first shard identifier.

16. A computer program product, tangibly stored on a non-transitory computer readable medium and comprising machine executable instructions, which are used to perform operations to manage an address mapping of a storage system, wherein a group of data objects in the storage system are mapped to a group of buckets in the address mapping, and wherein the group of buckets are divided into a first group of active shards that are associated with a group of storage devices in the storage system, respectively, the operations comprising:

receiving a first write request for writing a data object to the storage system;

adjusting a shard count of active shards in the first group of active shards based on an access load of the storage system and a load threshold condition of the storage system, wherein the load threshold condition comprises an upper threshold, and the adjusting the shard count of active shards in the first group of active shards comprises increasing the shard count in response to determining that the access load of the storage system is higher than a lower threshold;

updating the address mapping so as to map the data object to a bucket in the group of buckets, resulting in an updated address mapping;

instructing the storage system to store the data object to a storage device in the group of storage devices, the storage device being associated with an active shard to which the bucket belongs; and

managing the storage system based on the updated address mapping.

17. The computer program product of claim 16 , wherein the managing the storage system based on the updated address mapping comprises: in response to determining a state of the storage system meeting a predetermined regeneration condition,

identifying the first group of active shards as a first group of inactive shards; and

dividing the group of buckets into a second group of active shards.

18. The computer program product of claim 17 , wherein the predetermined regeneration condition comprises a threshold count of data objects associated with a shard, and the acts further comprise:

regarding a given active shard in the first group of active shards, determining an object count of data objects associated with the given active shard; and

dividing the group of buckets into a second group of active shards in response to determining the object count is higher than the threshold count.

19. The computer program product of claim 16 , wherein the load threshold condition comprises the lower threshold, and the adjusting the shard count of active shards in the first group of active shards comprises:

decreasing the shard count in response to determining the access load of the storage system is lower than the lower threshold.

20. The computer program product of claim 16 , wherein the managing the storage system based on the updated address mapping comprises:

determining a data distribution of a plurality of data objects in the first group of active shards; and

merging successive active shards in the first group of active shards based on the data distribution.