Triangular asynchronous replication

Software, provided in a computer readable storage medium, that causes recovery data to be stored, the software comprising:

• executable code that accumulates chunks of data corresponding to writes, wherein data written after a first time and before a second time is associated with a first chunk of data and data written after the second time is associated with a second chunk of data different than the first chunk of data;
• executable code that provides chunks of data to a remote destination while accumulating writes for the second chunk of data;
• executable code that sends a message to the remote destination following providing the first chunk of data to the remote destination;
• executable code that transmits the second chunk of data to the remote destination in response to receiving a reply to the message;
• executable code that provides synchronous data to a local destination;
• and
• executable code that provides an indicator to the local destination in connection with receiving the reply from the remote destination.

A system for storing recovery data, comprising:

• a source group that includes a plurality of storage devices, at least one of the storage devices accumulating chunks of data corresponding to writes thereto, wherein data written after a first time and before a second time is associated with a first chunk of data and data written after the second time is associated with a second chunk of data different than the first chunk of data;
• a remote destination coupled to the source group to receive therefrom chunks of data, wherein the source group provides the first chunk of data to the remote destination while accumulating writes for the second chunk of data, sends a message to the remote destination following providing the first chunk of data to the remote destination, and, in response to receiving a reply to the message, transmits the second chunk of data to the remote destination;
• and
• a local destination coupled to the source group to receive synchronous data therefrom, wherein the source group provides an indicator to the local destination in connection with receipt of the message from the remote destination.