Secondary storage protection

A secure backup method comprising:

• switching a backup storage appliance from being a read-only appliance to being a read/write appliance, the backup storage appliance is the read/write appliance for a designated backup window of time;
• storing a backup copy of a generation-1 data volume in the backup storage appliance only during the designated backup window of time, the generation-1 data volume is divided into a plurality of equal extents, the backup copy received from a primary storage server system;
• taking a first snapshot SS1 of the generation-1 data volume essentially immediately upon completion of the storing step;
• maintaining the first snapshot SS1 in a snapshot database in the backup storage appliance;
• immediately after the taking step, switching the backup storage appliance to being the read-only appliance;
• after a predesignated amount time, switching the backup storage appliance from being the read-only appliance to being the read/write appliance and retaining only changed extents from the plurality of equal extents in the backup storage appliance, the changed extents correspond to gen-1 extents from the generation-1 data volume;
• taking a second snapshot SS2 of the changed extents and maintaining the second snapshot SS2 in the snapshot database,
• the backup storage appliance is independent from and spaced away from a primary storage server system.

A backup system comprising:

• at a first end, a primary storage server system connected to a backup storage appliance via a private undiscoverable connection connected, the primary storage server system connected to a public network at a second end;
• the backup storage appliance in possession of a generation-1 data volume that comprises a sequence of equal primary extents,
• a first set of changed extents corresponding to a first subset of the equal primary extents, and
• a second set of changed extents corresponding to a second subset of either the equal primary extents, a subset of the changed extents, or a combination of the second subset of either the equal primary extents and the subset of the changed extents;
• a snapshot database in the backup storage appliance comprising a first snapshot SS1 of the equal primary extents, a second snapshot SS2 of the subset of the first set of changed extents, and a third snapshot SS3 of the second set of changed extents,
• the equal primary extents from only the primary storage server system;
• and
• the backup storage appliance only capable of storing the equal primary extent, the first set of changed extents and the second set of changed extents and taking the first snapshot SS1, the second snapshot SS2 and the third snapshot SS3 during scheduled read/write periods of time, between the scheduled read/write periods of time, the backup storage appliance is a read-only backup storage appliance.