Log cleaning and tiering in a log-based data storage system

A computer program product having a non-transitory computer readable medium which stores a set of instructions to clean a log structure, the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of:

• identifying a plurality of used extents to reclaim for reuse from a first storage tier of a set of storage tiers containing the log structure;
• performing a tier selection operation to select a target storage tier from the set of storage tiers based on a utilization measure of the log structure;
• and
• after identifying the plurality of used extents to reclaim and performing the tier selection operation, storing data from the identified used extents into a new extent of the target storage tier and freeing the used identified extents for reuse,
• wherein performing the tier selection operation to select the target storage tier includes:
• choosing, as the target storage tier, one of the first storage tier and a second storage tier that is different from the first storage tier, based on a utilization measure of the first storage tier, the utilization measure of the first storage tier being different from the utilization measure of the log structure.

Data storage equipment, comprising:

• a set of storage tiers containing a log structure;
• memory;
• and
• control circuitry coupled to the set of storage tiers and the memory, the memory storing instructions which, when carried out by the control circuitry, cause the control circuitry to:
• identify a plurality of extents to reclaim from a first storage tier of the set of storage tiers containing the log structure;
• perform a tier selection operation to select a target storage tier from the set of storage tiers based on a utilization measure of the log structure;
• and
• after identifying the plurality of extents to reclaim and performing the tier selection operation, store data from the identified extents into a new extent of the target storage tier and free the identified extents to clean the log structure,
• wherein the control circuitry, when performing the tier selection operation to select the target storage tier, is constructed and arranged to:
• choose, as the target storage tier, one of the first storage tier and a second storage tier that is different from the first storage tier, based on a utilization measure of the first storage tier, the utilization measure of the first storage tier being different from the utilization measure of the log structure.