Patent ID: 9734028
Date: 2017-08-15
CPC Classifications: G06F

Claim:
1. A method, comprising: configuring a first storage system to perform a first mirroring operation comprising mirroring first storage regions to corresponding second storage regions in a second storage system via a first data connection, and to perform a second mirroring operation comprising mirroring the first storage regions to corresponding third storage regions in a third storage system via a second data connection; detecting a failure in the first storage system; receiving, by the second storage system subsequent to detecting the failure, a request from a host computer to retrieve data from a given second storage region; determining that a respective timestamp of the corresponding third storage region on the third storage system is more recent than the respective timestamp of the given second storage region on the second storage system; retrieving, by the second storage system via a third data connection, the data from the corresponding third storage region on the third storage system, in response to the received request; and upon detecting the failure in the first data connection, performing a reverse resynchronization process comprising identifying any of the third storage regions whose respective timestamp that is more recent than the respective timestamp of the corresponding second storage region, and copying each given identified third storage region to the corresponding second storage region.