Migrating applications over asynchronous distances using semi-synchronous acceleration

A non-transitory computer-readable medium containing software that transfers an application from a first site to a second site, the software comprising:

• executable code that controls transitioning into a semi-synchronous mode by grouping writes by the application into delta sets to provide write order consistency, a first delta set being closed to finish pending writes by the application thereto and a second, different, delta set being opened and accepting new writes from the application after closing the first delta set and after a last one of the writes completes to the first delta set;
• executable code that propogates writes by the application at the first site to the second site and wherein, during the transitioning into the semi-synchronous mode, data written by the application at the first site to the first delta set is subsequently transferred to the second site while the first site is accepting the writes by the application to the second delta set;
• executable code that synchronizes cache data for the application between the first site and the second site by copying modified data from the first site to the second site, wherein the modified data is separate from data provided in the delta sets and wherein propagating writes by the application at the first site to the second site results in the cache data remaining unchanged;
• executable code that suspends operation of the application on the first site following completion of synchronizing cache data;
• and
• executable code that resumes operation of the application on the second site.

An active/active system, comprising:

• a first site;
• a second site located remotely from the first site, wherein each of the first site and the second site include at least one host cluster, at least one director cluster, and at least one storage array;
• and
• a computer readable medium of at least one of:
• the host cluster or the director cluster that stores software for providing mobility of an application between the first site and the second site, the software including:
• executable code that controls transitioning into a semi-synchronous mode by grouping writes by the application into delta sets to provide write order consistency, a first delta set being closed to finish pending writes by the application thereto and a second, different, delta set being opened and accepting new writes from the application after closing the first delta set and after a last one of the writes completes to the first delta set;
• executable code that propogates writes by the application at the first site to the second site and wherein, during the transitioning into the semi-synchronous mode, data written by the application at the first site to the first delta set is subsequently transferred to the second site while the first site is accepting the writes by the application to the second delta set;
• executable code that synchronizes cache data for the application between the first site and the second site by copying modified data from the first site to the second site, wherein the modified data is separate from data provided in the delta sets and wherein propagating writes by the application at the first site to the second site results in the cache data remaining unchanged;
• executable code that suspends operation of the application on the first site following completion of synchronizing cache data;
• and
• executable code that resumes operation of the application on the second site.