近期有个生产系统，计划做一套dr-autosync的集群，但是之前并没有这种类型系统的生产实施经验，就一点点的摸索，好在最后是顺利搭建成功了，把搭建过程分享出来给大家参考下。

1、集群架构

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2、规划拓扑

根据集群架构规划拓扑文件

global: user: "tidb" ssh_port: 22 deploy_dir: "/tidb/tidb-deploy" data_dir: "/tidb/tidb-data" arch: "arm64" monitored: node_exporter_port: 19100 blackbox_exporter_port: 19115 server_configs: tidb: tikv: pd: dashboard.enable-telemetry: false log.file.max-backups: 100 log.file.max-days: 90 replication.isolation-level: logic replication.location-labels: - dc - logic - rack - host replication.max-replicas: 5 schedule.max-store-down-time: 30m pd_servers: - host: 10.3.65.1 client_port: 12379 peer_port: 12380 - host: 10.3.65.2 client_port: 12379 peer_port: 12380 - host: 10.3.65.3 client_port: 12379 peer_port: 12380 - host: 10.3.65.1 client_port: 12379 peer_port: 12380 - host: 10.3.65.2 client_port: 12379 peer_port: 12380 tidb_servers: - host: 10.3.65.1 port: 24000 status_port: 20080 - host: 10.3.65.2 port: 24000 status_port: 20080 - host: 10.3.65.3 port: 24000 status_port: 20080 - host: 10.3.65.1 port: 24000 status_port: 20080 - host: 10.3.65.2 port: 24000 status_port: 20080 - host: 10.3.65.3 port: 24000 status_port: 20080 tikv_servers: - host: 10.3.65.1 port: 20160 status_port: 20180 config: server.labels: dc: dc1 logic: logic1 rack: rack1 host: host1 - host: 10.3.65.2 port: 20160 status_port: 20180 config: server.labels: dc: dc1 logic: logic2 rack: rack1 host: host1 - host: 10.3.65.3 port: 20160 status_port: 20180 config: server.labels: dc: dc1 logic: logic3 rack: rack1 host: host1 - host: 10.3.65.1 port: 20160 status_port: 20180 config: server.labels: dc: dc2 logic: logic4 rack: rack1 host: host1 - host: 10.3.65.2 port: 20160 status_port: 20180 config: server.labels: dc: dc2 logic: logic5 rack: rack1 host: host1 - host: 10.3.65.3 port: 20160 status_port: 20180 config: server.labels: dc: dc2 logic: logic6 rack: rack1 host: host1 monitoring_servers: - host: 10.3.65.3 port: 29090 ng_port: 22020 grafana_servers: - host: 10.3.65.3 port: 23000 alertmanager_servers: - host: 10.3.65.3 web_port: 29093 cluster_port: 29094

3、集群部署

1、部署集群

tiup cluster deploy dr-auto-sync v6.5.4 dr-auto-sync.yaml --user tidb -p

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2、编写dr-auto-sync集群的json文件

vim rule.json

[ { "group_id": "pd", "group_index": 0, "group_override": false, "rules": [ { "group_id": "pd", "id": "dc1", "start_key": "", "end_key": "", "role": "voter", "count": 3, "location_labels": ["dc", "logic", "rack", "host"], "label_constraints": [{"key": "dc", "op": "in", "values": ["dc1"]}] }, { "group_id": "pd", "id": "dc2", "start_key": "", "end_key": "", "role": "follower", "count": 2, "location_labels": ["dc", "logic", "rack", "host"], "label_constraints": [{"key": "dc", "op": "in", "values": ["dc2"]}] }, { "group_id": "pd", "id": "dc2-1", "start_key": "", "end_key": "", "role": "learner", "count": 1, "location_labels": ["dc", "logic", "rack", "host"], "label_constraints": [{"key": "dc", "op": "in", "values": ["dc2"]}] } ] } ]

3、配置placement rule json文件，使其生效

[tidb@tidb141 ~]$ tiup ctl:v6.5.4 pd -u 10.3.65.141:22379 -i ? config placement-rules rule-bundle save --in="/home/tidb/rule.json"

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检查配置是否生效

? config placement-rules show

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4、修改dr-auto-sync 模式

config set replication-mode dr-auto-sync

5、配置dr-auto-sync 的机房标签

config set replication-mode dr-auto-sync label-key dc

6、配置主机房

config set replication-mode dr-auto-sync primary dc1

7、配置从机房

config set replication-mode dr-auto-sync dr dc2

8、配置主机房副本数量

config set replication-mode dr-auto-sync primary-replicas 3

9、配置从机房副本数量

config set replication-mode dr-auto-sync dr-replicas 2

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10、如果集群为跨机房部署的dr-auto-sync 架构，需要确保pd leader 始终位于主机房，可以配置主机房pd权重高于备机房，数值越大权重越高，越优先考虑成为pd leader

tiup ctl:v6.5.3 pd –u 192.168.113.1:12379 -i member leader_prioritypd-192.168.113.1-12379 100 member leader_prioritypd-192.168.113.2-12379 100 member leader_prioritypd-192.168.113.3-12379 100 member leader_prioritypd-192.168.113.4-12379 50 member leader_prioritypd-192.168.113.5-12379 50

11、检查集群同步状态

[tidb@tidb141 ~]$ curl http://10.3.65.141:22379/pd/api/v1/replication_mode/status

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4、测试

1、手动关停备机房tikv节点，等待约一分钟左右，检查同步级别是否自动降级为async

[tidb@tidb141 ~]$ tiup cluster stop dr-auto-sync -N 10.3.65.142:10160,10.3.65.142:40160,10.3.65.142:50160

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同步级别自动降级为async（异步）

2、启动关停的tikv节点，等待约一分钟左右，检查同步级别是否自动升级为sync

[tidb@tidb141 ~]$ tiup cluster start dr-auto-sync -N 10.3.65.142:10160,10.3.65.142:40160,10.3.65.142:50160

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同步级别自动升级为sync，符合预期

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至此，dr-auto-sync集群部署成功

5、总结

dr-auto-sync集群，较普通集群其实区别不大，只要按需规划好集群拓扑及、abels、json文件，基本上不会有什么问题，把它当作普通集群部署就可以，但有几点需要注意：

1、跨机房的话，需要配置pd的权重，防止pd leader跑到备机房，影响整体性能

2、我使用的6.5.4版本，dr-auto-sync有个bug，配置完成后，需要reload一下tikv节点，触发region leader重新选举，同步链路才会升级为sync状态，否则会一直卡在sync_recover阶段