Reducing Power Consumption of Distributed Storage Systems

A method of storing data objects in a storage system, the system comprising a plurality of groups of servers and the method comprising:

• dividing each data object into a plurality of chunks of data;
• for each chunk of data, storing a block of data derived from the chunk of data on each of a number of servers in different groups;
• and
• operating the system in one of a plurality of operating modes selected based on system load, the plurality of operating modes comprising:
• a first mode in which a first number of blocks of data derived from a chunk of data are available;
• and
• at least one reduced power mode in which at least one group of servers are put into a low power state such that a subset of blocks of data derived from each chunk of data are available and in which data written to the storage system is stored in a versioned store.

A storage system for storing a plurality of data objects, each data object comprising at least one chunk of data and the system comprising:

• a plurality of servers arranged to store chunks of data and wherein each chunk is replicated across a number of servers;
• a metadata service storing mappings between data objects and chunks of data;
• a scheduling service arranged to predict system load and at times of reduced system load to schedule a subset of the servers to enter a low power mode such that a reduced number of replicas of a chunk of data are available;
• and
• a versioned store arranged to store data written when at least one server is in a low power mode and to transfer the data stored to the servers when all servers have exited from the low power mode.