Region migration
Region migration allows users to move regions between the Datanode.
Warning
This feature is only available on GreptimeDB running on cluster mode and
- Using Kafka WAL
- Using shared storage (e.g., AWS S3)
Otherwise, you can't perform a region migration.
Figure out the MetaSrv leader
The region migration procedure is only allowed to submit to the MetaSrv leader; we need to figure out which MetaSrv is a leader.
curl {YOUR_META_SRV_SERVER}:3002/admin/leader
# 10.244.0.157:3002curl {YOUR_META_SRV_SERVER}:3002/admin/leader
# 10.244.0.157:3002Figure out the region distribution of the table.
To figure out a table's region distribution, we need to send a route query to the MetaSrv, using the YOUR_META_SRV_LEADER_SERVER address we obtained before.
curl {YOUR_META_SRV_LEADER_SERVER}:3002/admin/route?table_id={TABLE_ID}
# "{\"type\":\"physical\",\"region_routes\":[{\"region\":{\"id\":4668629450752,\"name\":\"\",\"partition\":{\"column_list\":[],\"value_list\":[\"\\\"MaxValue\\\"\"]},\"attrs\":{}},\"leader_peer\":{\"id\":2,\"addr\":\"greptimedb-datanode-2.greptimedb-datanode.my-greptimedb:4001\"},\"follower_peers\":[]}],\"version\":2}"curl {YOUR_META_SRV_LEADER_SERVER}:3002/admin/route?table_id={TABLE_ID}
# "{\"type\":\"physical\",\"region_routes\":[{\"region\":{\"id\":4668629450752,\"name\":\"\",\"partition\":{\"column_list\":[],\"value_list\":[\"\\\"MaxValue\\\"\"]},\"attrs\":{}},\"leader_peer\":{\"id\":2,\"addr\":\"greptimedb-datanode-2.greptimedb-datanode.my-greptimedb:4001\"},\"follower_peers\":[]}],\"version\":2}"For example, we have the following region distribution:
| region id | leader_peer | leader_peer_id |
|---|---|---|
| 4668629450752 | greptimedb-datanode-2.greptimedb-datanode.my-greptimedb:4001 | 2 |
Select a Datanode as the migration destination.
Warning
The region migration won't be performed if the from_peer_id equals the to_peer_id.
Remember, if you deploy the cluster via the GreptimeDB operator, the peer_id of Datanode always starts from 0. For example, if you have a 3 Datanode GreptimeDB cluster, the available peer_id will be 0,1,2.
Finally, you can do a Region migration request via the following HTTP request:
curl "{YOUR_META_SRV_LEADER_SERVER}:3002/admin/region-migration?region_id={REGION_ID}&from_peer_id={FROM_PEER_ID}&to_peer_id={TO_PEER_ID}&replay_timeout=5m"curl "{YOUR_META_SRV_LEADER_SERVER}:3002/admin/region-migration?region_id={REGION_ID}&from_peer_id={FROM_PEER_ID}&to_peer_id={TO_PEER_ID}&replay_timeout=5m"| Option | Description | Required | |
|---|---|---|---|
region_id | The region id. | Required | |
from_peer_id | The peer id of the migration source(Datanode). | Required | |
to_peer_id | The peer id of the migration destination(Datanode). | Required | |
replay_timeout | The timeout of replay data. e.g., 1h30m10s | Required |