Patent attributes
In one aspect, a method includes running a virtual machine (VM) at a first site, sending I/Os from the VM to a first virtual volume (VVol) at the first site, mirroring the first VVol with a second VVol at a second site, sending I/Os for the first VVol to a third VVol at a third site, detecting failure at the first site, running the VM at the second site, reading a second backlog, adding the second backlog to a delta marker on the second site, the delta marker storing differences between the third VVol and the second VVol and replicating the second VVol to the third VVol after adding the second backlog to the delta marker. The second backlog is synchronized with a first backlog on the first site and the first backlog stores I/Os that have not been completed to the third VVol.
