# US 10,771,551 B2 · Dynamic topology switch for data replication > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,771,551 B2 - Document ID: US10771551B2 - Status: Granted - Kind: B2 - Application number: 15/471,294 - Filed: 2017-03-28 - Published: 2018-10-04 - Granted: 2020-09-08 - Earliest claimed: 2017-03-28 - Assignees: Sap SE - Applicants: Sap SE - Inventors: Zheng-Wei Wang; Jian Luo; Yi Chen; Weizhong Qiu; Huizi Liu; Du Xue - Web page: https://patentgrep.com/patent/US10771551B2 ## CPC - H04L 67/1095: Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes - H04L 41/0663: Performing the actions predefined by failover planning, e.g. switching to standby network elements - H04L 41/12: Discovery or management of network topologies - H04L 69/40: for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection (management of faults, events, alarms or notifications in data switching networks H04L41/06) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present disclosure involves systems, software, and computer implemented methods for performing dynamic topology switch in a failover operation. In one example, a failover of a first node is determined. The first node includes a first data server and a first replication server. At least one user application connects to the first data server prior to the failover of the first node. In response to the determined failover, the at least one user application is connected to a second data server of a second node. The second node includes the second data server and a second replication server. Prior to the failover of the first node, a data replication topology of the second node is a remote topology. During the failover, if the first replication server on the first node is down, the data replication topology of the second node is switched from the remote topology to a local topology. ## Claims ### Claim 1 A non-transitory computer storage medium encoded with a computer program, the program comprising instructions that, when executed by one or more computers, cause the one or more computers to perform operations comprising: determining a failover of a first node, wherein the first node includes a first data server and a first replication server, and wherein at least one user application connects to the first data server prior to the failover of the first node; in response to the determined failover of the first node including a failure of the first replication server: connecting the at least one user application to a second data server of a second node, wherein the second node includes the second data server and a second replication server, and wherein a data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, switching the data replication topology of the second data server from the remote topology to a local topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system, wherein, in the local topology, replication data of the second data server in the second node is routed from the second data server in the second node through the second replication server in the second node to the external replication system, and wherein prior to the failover of the first node, replication data of the first data server in the first node is routed from the first data server in the first node through the second replication server in the second node to the external replication system; and in response to the determined failover of the first node not including a failure of the first replication server: connecting the at least one user application to the second data server of the second node, wherein the second node includes the second data server and the second replication server, and wherein the data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, maintaining the data replication topology of the second data server as the remote topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system. ### Claim 2 (depends on 1) The medium of claim 1, wherein the failover of the first node is an unplanned failover, and wherein the unplanned failover is triggered by a failure of both the first data server and the first replication server. ### Claim 3 (depends on 1) The medium of claim 1, wherein the switching is performed automatically in response to the determined failover of the first node. ### Claim 4 (depends on 1) The medium of claim 1, further comprising: determining a recovery of the first replication server of the first node; and switching the data replication topology of the second data server from the local topology to the remote topology. ### Claim 5 (depends on 4) The medium of claim 4, wherein the at least one user application connects to the second data server after switching the data replication topology of the second data server from the local topology to the remote topology. ### Claim 6 (depends on 4) The medium of claim 4, wherein switching the data replication topology of the second data server from the local topology to the remote topology is performed automatically, in response to the determined recovery of the first replication server of the first node. ### Claim 7 (depends on 4) The medium of claim 4, wherein switching the data replication topology of the second data server from the local topology to the remote topology is performed manually, in response to the determined recovery of the first replication server of the first node, wherein the determined recovery of the first replication server of the first node includes an indication of the determined recovery being provided to a user. ### Claim 8 (depends on 1) The medium of claim 1, wherein the first node, the second node, and the external replication system are in an adaptive server enterprise (ASE) high availability disaster recovery (HADR) with external replication system, and the first and second data servers are ASE data servers. ### Claim 9 A computerized method performed by one or more processors, the method comprising: determining a failover of a first node, wherein the first node includes a first data server and a first replication server, and wherein at least one user application connects to the first data server prior to the failover of the first node; in response to the determined failover of the first node including a failure of the first replication server: connecting the at least one user application to a second data server of a second node, wherein the second node includes the second data server and a second replication server, and wherein a data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, switching the data replication topology of the second data server from the remote topology to a local topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system, wherein, in the local topology, replication data of the second data server in the second node is routed from the second data server in the second node through the second replication server in the second node to the external replication system, and wherein prior to the failover of the first node, replication data of the first data server in the first node is routed from the first data server in the first node through the second replication server in the second node to the external replication system; and in response to the determined failover of the first node not including a failure of the first replication server: connecting the at least one user application to the second data server of the second node, wherein the second node includes the second data server and the second replication server, and wherein the data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, maintaining the data replication topology of the second data server as the remote topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system. ### Claim 10 (depends on 9) The method of claim 9, wherein the failover of the first node is an unplanned failover, and wherein the unplanned failover is triggered by a failure of both the first data server and the first replication server. ### Claim 11 (depends on 9) The method of claim 9, wherein the switching is performed automatically in response to the determined failover of the first node. ### Claim 12 (depends on 9) The method of claim 9, further comprising: determining a recovery of the first replication server of the first node; and switching the data replication topology of the second data server from the local topology to the remote topology. ### Claim 13 (depends on 12) The method of claim 12, wherein the at least one user application connects to the second data server after switching the data replication topology of the second data server from the local topology to the remote topology. ### Claim 14 (depends on 12) The method of claim 12, wherein switching the data replication topology of the second data server from the local topology to the remote topology is performed automatically, in response to the determined recovery of the first replication server of the first node. ### Claim 15 (depends on 12) The method of claim 12, wherein switching the data replication topology of the second data server from the local topology to the remote topology is performed manually, in response to the determined recovery of the first replication server of the first node, wherein the determined recovery of the first replication server of the first node includes an indication of the determined recovery being provided to a user. ### Claim 16 (depends on 9) The method of claim 9, wherein the first node, the second node, and the external replication system are in an adaptive server enterprise (ASE) high availability disaster recovery (HADR) with external replication system, and the first and second data servers are ASE data servers. ### Claim 17 A system comprising: one or more processors; and a computer-readable medium storing instructions executable by the one or more processors to perform operations comprising: determining a failover of a first node, wherein the first node includes a first data server and a first replication server, and wherein at least one user application connects to the first data server prior to the failover of the first node; in response to the determined failover of the first node including a failure of the first replication server: connecting the at least one user application to a second data server of a second node, wherein the second node includes the second data server and a second replication server, and wherein a data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, switching the data replication topology of the second data server from the remote topology to a local topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system, wherein, in the local topology, replication data of the second data server in the second node is routed from the second data server in the second node through the second replication server in the second node to the external replication system, and wherein prior to the failover of the first node, replication data of the first data server in the first node is routed from the first data server in the first node through the second replication server in the second node to the external replication system; and in response to the determined failover of the first node not including a failure of the first replication server: connecting the at least one user application to the second data server of the second node, wherein the second node includes the second data server and the second replication server, and wherein the data replication topology of the second data server is a remote topology; and in response to connecting the at least one user application to the second data server of the second node, maintaining the data replication topology of the second data server as the remote topology, wherein, in the remote topology, replication data of the second data server in the second node is routed from the second data server in the second node through the first replication server in the first node to an external replication system. ### Claim 18 (depends on 17) The system of claim 17, wherein the failover of the first node is an unplanned failover, and wherein the unplanned failover is triggered by a failure of both the first data server and the first replication server.