Use of timestamp logic in synchronous replication

摘要

Systems and methods for maintaining data consistency across mirrored storage nodes. Data consistency may be maintained in networked storage environments using a timestamp of an I/O in the primary and secondary servers (also referred to as nodes) in synchronous replication to re-synchronize the data efficiently, without much performance drop and while reducing the memory footprint. According to an aspect presented herein, data consistency is maintained in a mirror node by timestamping the I/O for a volume's logical territory in both the primary and secondary nodes. The timestamp acts as a watermark. Thus, whenever a disaster or failure occurs, the watermark point determines the re-synchronization point.

主权项

1. A method of using timestamps in a synchronous replication between a first volume and a second volume, comprising:
maintaining a global time segment number that is incremented in time; logging a current global time segment number for each write to a provision with a territory within a redundant array of inexpensive disk (RAID) volume, the logging of the current global time segment number for each write being performed if a territory time segment number is less than the current global time segment number for each write being performed at a territory granularity; determining a restoration of replication between the first volume and the second volume after a failure has been detected; determining a last global time segment number where replication was successful and declaring the last global time segment as a watermark; and restoring I/Os to the second volume from the first volume from that occurred since the watermark.