Server Based Disaster Recovery by Making Use of Dual Write Responses

摘要

A mechanism is provided in a data processing system for asynchronous replication. The mechanism creates a record in a write log in a host computing device for a write command and marking the record as uncommitted. The mechanism maintains a copy of data to be written by the write command at the host computing device. The mechanism issues the write command from the host computing device to a primary storage controller at the primary storage site. Responsive to receiving an acknowledgement from the primary storage controller that the data have been written to the primary storage site, the mechanism marks the record as unreplicated. Responsive to receiving an acknowledgement from the primary storage controller that the data have been replicated to a secondary storage site, the mechanism erases the record in the write log and deleting the copy of data.

主权项

1. A computer program product comprising a non-transitory computer readable storage medium having a computer readable program stored therein, wherein the computer readable program, when executed on a host computing device, causes the host computing device to:
maintain a copy of data to be written by a write command to write data to a primary storage site at the host computing device; issue the write command from the host computing device to a primary storage controller at the primary storage site; create a tracker command having a reference to the write command; issue the tracker command from the host computing device to the primary storage controller; exchange an association between the write command and the tracker command with the primary storage controller, wherein the primary storage controller creates a record in a local log at the primary storage site for the tracker command and wherein the primary storage controller returns an acknowledgement associated with the tracker command responsive to the data being replicated to the secondary storage site; and responsive to receiving an acknowledgement from the primary storage controller that the data have been replicated to a secondary storage site, erase the record in the write log and delete the copy of data in the host computing device.