Patent ID: 9384255
Filing Date: 2016-07-05
CPC Classification: G06F

Claim Text:
1. A method comprising: storing a version of a disk at a first site, the disk storing input/output for a host system; storing a version of the disk at a second site that is remote from the first site, wherein the version of the disk at the second site is a synchronous replication of the version at the first site; storing a version of the disk at a third site that is remote from the first site and the second site, wherein the version of the disk at the third site is an asynchronous replication of the version at the first site; synchronizing the version of the disk at the first site with the version at the third site if the version at the first site needs synchronizing and the version at the second site is unavailable; and synchronizing the version of the disk at the second site with the version at the third site if the version at the second site needs synchronizing and the version at the first site is unavailable; and wherein storing a version of a disk at the first site comprises storing a first version and a second version of the disk at the first site, wherein the second version of the disk is a point-in-time copy of the first version; storing a version of the disk at the second site comprises storing a first version and a second version of the disk at the second site, wherein the first version of the disk at the second site is a synchronous replication of the first version at the first site, and the second version of the disk at the second site is a point-in-time copy of the first version at the second site; and storing a version of the disk at the third site comprises storing a first version, a second version, and a third version of the disk at the third site, wherein the first version of the disk at the third site is an intermittent synchronous replication of the second version at the first site, the second version of the disk at the third site is a point-in-time copy of the first version at the third site, and the third version of the disk at the third site is a point-in-time copy of the first version at the third site.