chore: add example configs that introduced after pg_kvbackend

config/config.md

@@ -264,6 +264,7 @@
 | `enable_telemetry` | Bool | `true` | Whether to enable greptimedb telemetry. |
 | `store_key_prefix` | String | `""` | If it's not empty, the metasrv will store all data with this key prefix. |
 | `enable_region_failover` | Bool | `false` | Whether to enable region failover.<br/>This feature is only available on GreptimeDB running on cluster mode and<br/>- Using Remote WAL<br/>- Using shared storage (e.g., s3). |
+| `backend` | String | `etcd_store` | The datastore for metasrv. |
 | `runtime` | -- | -- | The runtime options. |
 | `runtime.global_rt_size` | Integer | `8` | The number of threads to execute the runtime for global read operations. |
 | `runtime.compact_rt_size` | Integer | `4` | The number of threads to execute the runtime for global write operations. |

config/metasrv.example.toml

@@ -7,7 +7,7 @@ bind_addr = "127.0.0.1:3002"
 ## The communication server address for frontend and datanode to connect to metasrv,  "127.0.0.1:3002" by default for localhost.
 server_addr = "127.0.0.1:3002"
 
-## Etcd server address.
+## Store server address default to etcd store.
 store_addr = "127.0.0.1:2379"
 
 ## Datanode selector type.
@@ -32,6 +32,9 @@ store_key_prefix = ""
 ## - Using shared storage (e.g., s3).
 enable_region_failover = false
 
+## The datastore for meta server.
+backend = "etcd_store"
+
 ## The runtime options.
 [runtime]
 ## The number of threads to execute the runtime for global read operations.