Patent ID: 8234464

Claim:
A hybrid data storage system comprising: at least one first data storage cluster configured to store data and having high data storage capacity; and at least one second data storage cluster configured to store data and having lower data storage capacity than said first data storage cluster; said data initially replicated and stored by at least one said first and at least one said second data storage cluster; said at least one second data storage cluster configured to identify a portion of said stored initially replicated data as “pinned”, to identify at least another portion of said initially replicated data as “pinned for a limited period of time”, and to continue to store said pinned initially replicated data, and to continue to store said identified “pinned for a limited period of time” data for at least a predetermined limited period of time from initial storage or last access of said data; and to selectively remove non-pinned said initially replicated data, and said “pinned for a limited period of time” data for which said predetermined limited period of time has expired and been reset to “non-pinned”, from said at least one second data storage cluster.