Scheduling policy for queues in a non-volatile solid-state storage

A storage cluster, comprising:

• a plurality of storage nodes within a single chassis;
• each of the plurality of storage nodes having nonvolatile solid-state memory for storage of user data, the nonvolatile solid-state memory comprising:
• a plurality of operation queues;
• a plurality of channel busses, configured to couple the plurality of operation queues to a non-volatile memory, each of the plurality of channel busses having a channel;
• a processor, configured to perform repeating actions including:
• determining a relative benefit of each of a plurality of operations in the plurality of operation queues, based on a plurality of policies, the plurality of policies including assigning sequential addresses, within a bounded address space, to newly arriving data write operations, wherein a first data write resulting from a garbage collection is accorded a lower benefit than a second data write of the newly arriving data write operations as a result of the first data write referencing a lower address than the second data write;
• determining for each channel one of the plurality of operations in the plurality of operation queues having a greater relative benefit than others of the plurality of operations in the plurality of operation queues;
• and
• performing, for each channel, the determined one of the plurality of operations.

A storage cluster comprising:

• a plurality of storage nodes within a single chassis;
• each of the plurality of storage nodes having nonvolatile solid-state memory for storage of user data, the nonvolatile solid-state memory comprising:
• a non-volatile memory;
• a controller, coupled to the non-volatile memory;
• a plurality of queues, coupled to or included in the controller, the plurality of queues coupled to the non-volatile memory by a plurality of channels, each of the plurality of queues configured to hold therein a plurality of operations relating to the non-volatile memory;
• and
• the controller configured to perform actions including:
• weighting each operation in each of the plurality of queues, according to a plurality of policies, the plurality of policies including assigning sequential addresses, within a bounded address space, to newly arriving data write operations, wherein a first data write resulting from a garbage collection is accorded a lower benefit than a second data write of the newly arriving data write operations as a result of the first data write referencing a lower address than the second data write;
• selecting, for each of the plurality of channels, a next operation from the plurality of queues, according to the weighting;
• and
• executing, for each of the plurality of channels, the next operation.