迁移数据库分片

如何将数据库分片迁移到 Redis Software 集群中的其他节点。

Redis 企业软件

要将数据库分片迁移到集群中的其他节点，您可以使用rladmin migrate命令或 REST API 请求。

分片迁移的使用案例

在以下情况下，将数据库分片迁移到其他节点：

  • 在节点删除之前。

  • 在出现延迟问题或节点之间的负载分配不均匀时手动平衡数据库。

  • 管理节点资源，例如内存使用情况。

分片迁移的注意事项

对于具有复制功能的数据库：

  • 迁移分片不会导致中断，因为主分片仍然可用。

  • 如果您尝试迁移主分片，则它将被降级为副本分片，并且副本分片将在迁移之前提升为主分片。如果您将"preserve_roles": true在请求中，迁移完成后将进行第二次故障转移，以将迁移的分片的角色更改回主分片。

对于没有复制的数据库，在迁移完成之前，迁移的分片将不可用。

在这两种情况下，连接的客户端都不应断开连接。

如果在同一节点上放置了太多主分片，则可能会影响数据库性能。

迁移特定分片

要迁移特定的数据库分片，请使用以下方法之一：

  • rladmin migrate shard:

    rladmin migrate shard <shard_id> target_node <node_id>

  • Migrate shard REST API request:

    Specify the ID of the shard to migrate in the request path and the destination node's ID as the target_node_uid in the request body. See the request reference for more options.

    POST /v1/shards/<shard_id>/actions/migrate
{
    "target_node_uid": <node_id>
}

    Example JSON response body:

    {
    "action_uid": "<action_id>",
    "description": "Migrate was triggered"
}

    You can track the action's progress with a GET /v1/actions/<action_uid> request.

Migrate multiple shards

To migrate multiple database shards, use one of the following methods:

  • rladmin migrate shard:

    rladmin migrate shard <shard_id1> <shard_id2> <shard_id3> target_node <node_id>

  • Migrate multiple shards REST API request:

    Specify the IDs of the shards to migrate in the shard_uids list and the destination node's ID as the target_node_uid in the request body. See the request reference for more options.

    POST /v1/shards/actions/migrate
{
    "shard_uids": ["<shard_id1>","<shard_id2>","<shard_id3>"],
    "target_node_uid": <node_id>
}

    Example JSON response body:

    {
    "action_uid": "<action_id>",
    "description": "Migrate was triggered"
}

    You can track the action's progress with a GET /v1/actions/<action_uid> request.

Migrate all shards from a node

To migrate all shards from a specific node to another node, run rladmin migrate all_shards:

rladmin migrate node <origin_node_id> all_shards target_node <node_id>

Migrate primary shards

You can use the rladmin migrate all_master_shards command to migrate all primary shards for a specific database or node to another node in the cluster.

To migrate a specific database's primary shards:

rladmin migrate db db:<id> all_master_shards target_node <node_id>

To migrate all primary shards from a specific node:

rladmin migrate node <origin_node_id> all_master_shards target_node <node_id>

Migrate replica shards

You can use the rladmin migrate all_slave_shards command to migrate all replica shards for a specific database or node to another node in the cluster.

To migrate a specific database's replica shards:

rladmin migrate db db:<id> all_slave_shards target_node <node_id>

To migrate all replica shards from a specific node:

rladmin migrate node <origin_node_id> all_slave_shards target_node <node_id>
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