Dynamic modification of global cache capacity

A cache system for a computer cluster comprising a plurality of nodes, the cache system comprising:

• a global cache distributed over a subset of nodes of the computer cluster, a respective node in the subset contributing a portion of local storage resource to the global cache and running a cache-manager process to:
• monitor usage of the global cache;
• determine whether capacity of the global cache needs adjustment based on the monitored usage;
• in response to determining that the global cache needs additional storage capacity,
• identify a first node in the computer cluster capable of providing the additional storage capacity;
• send an add-capacity request to the first node;
• and
• add a portion of storage resource on the first node to the global cache;
• and
• in response to determining that the global cache needs to reduce storage capacity,
• identify a second node that contributes to the global cache;
• send a reduce-capacity request to the second node;
• and
• remove, from the global cache, at least a portion of storage resource contributed by the second node.

A non-transitory computer-readable storage medium storing instructions which when executed by a processor cause the processor to perform a method for dynamically adjusting capacity of a distributed global cache in a computer cluster, the method comprising:

• monitoring, by a cache-manager process running on a respective node of the computer cluster, usage of the global cache;
• determining whether capacity of the global cache needs adjustment based on the monitored usage;
• in response to determining that the global cache needs additional capacity,
• identifying a first node in the computer cluster capable of providing the additional capacity;
• sending an add-capacity request to the first node;
• and
• adding a portion of storage resource on the first node to the global cache;
• and
• in response to determining that the global cache needs to reduce capacity,
• identifying a second node that contributes to the global cache;
• sending a reduce-capacity request to the second node;
• and
• removing, from the global cache, at least a portion of storage resource contributed by the second node.