Cloud capacity scaling in metadata space constrained deduplication systems

A system comprising:

• a processor;
• and memory configured to store one or more sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of:
• migrating data from a deduplicated storage appliance to a cloud storage, the data to be stored at the cloud storage as a plurality of cloud units, each cloud unit comprising a plurality of containers comprising data containers storing segments of files, segment tree containers storing upper-level segments of segment trees representing the files, and cloud containers storing headers from the data and segment tree containers, wherein a header for a data container comprises fingerprints identifying the segments of files stored in the data container, and a header for a segment tree container comprises fingerprints identifying the upper-level segments stored in the segment tree container;
• maintaining different states of accessibility for the cloud units, the states of accessibility comprising a read-write state, a read-only state, and an offline state;
• detecting that local storage of the storage appliance does not have space to support a cloud unit in one of the read-write state or the read-only state;
• selecting another cloud unit that is in a first state, the first state being one of the read-write state or the read-only state;
• and
• placing the selected cloud unit in a second state, different from the first state, the placing comprising deleting from the local storage at least one of segment tree containers or cloud containers associated with the selected cloud unit.

A computer program product, comprising a non-transitory computer-readable medium having a computer-readable program code embodied therein, the computer-readable program code adapted to be executed by one or more processors to implement a method comprising:

• migrating data from a deduplicated storage appliance to a cloud storage, the data to be stored at the cloud storage as a plurality of cloud units, each cloud unit comprising a plurality of containers comprising data containers storing segments of files, segment tree containers storing upper-level segments of segment trees representing the files, and cloud containers storing headers from the data and segment tree containers, wherein a header for a data container comprises fingerprints identifying the segments of files stored in the data container, and a header for a segment tree container comprises fingerprints identifying the upper-level segments stored in the segment tree container;
• maintaining different states of accessibility for the cloud units, the states of accessibility comprising a read-write state, a read-only state, and an offline state;
• detecting that local storage of the storage appliance does not have space to support a cloud unit in one of the read-write state or the read-only state;
• selecting another cloud unit that is in a first state, the first state being one of the read-write state or the read-only state;
• and
• placing the selected cloud unit in a second state, different from the first state, the placing comprising deleting from the local storage at least one of segment tree containers or cloud containers associated with the selected cloud unit.