Patent ID: 8838919
Filing Date: 2014-09-16
Classification: G06F,Y10S

Abstract:
1. A method for determining data replication lag time comprising: a standby storage system receiving a stream of change records that record changes to data made at a primary storage system, each change record recording a change and including a system change value and a primary change time value, wherein the system change value identifies a particular state of data; wherein the primary change time value represents a time said change occurred, said primary change time value being generated by the primary storage system; said standby storage system maintaining a latest received primary system time value based on primary change time values recorded in the stream of change records; said standby storage system applying said stream of change records to data at said standby storage system; after said standby storage system applying, from said stream of change records, a particular change record having a particular system change value and a particular primary change time value, said standby storage system determining a data replication lag time for the particular system change value based on a difference between the latest received primary system time value and the particular primary change time value.