容灾技术培训-核心技术及概念解释.ppt

remote data replica veritas volume manager veritas volume replicator application availability veritas cluster server rlink rlink exact mirror copy at secondary location application performance impact is equal to network latency rlink rlink rlink rlink bitmap of regions on a primary volume that differ from the secondary volume no information on write order recovery involves copying all regions marked in the dcm to the secondary marks a position in the primary srl for the start of the copy when the copy is complete, mark the end on the srl replay all changes written to the primary rvg during the copy to the secondary rvg from the srl write goes to primary srl data is sent to vvr memory on secondary rvg destage to local disk on primary rvg secondary rvg acknowledges receipt (network acknowledgement) acknowledge application secondary rvg acknowledges data written to local disk (data acknowledgement) vvr layer vvr layer application layer total latency in synchronous replication involves 4 distinct areas local write to srl transmission delay to secondary rvg receive, process, and send network acknowledgement transmission delay to primary rvg items 2 and 4 usually take the most time vvr layer vvr layer application layer write goes to primary srl acknowledge application data is sent to vvr memory on secondary rvg destage to local disk on primary rvg secondary rvg acknowledges receipt (network acknowledgement) secondary rvg acknowledges data written to local disk (data acknowledgement) vvr layer vvr layer application layer ip ip snapshots to preserve data integrity requires additional storage (lots) delivers less-current data (rpo) rlink rlink license key enabled license key enabled primary data center secondary data center primary data center secondary data center primary data ce