placement rule产生过多副本

[h5n1]

【版本】 v5.2.2
集群设置5副本。label设置了3个层级：city,zone,host，其中city设置了3个：xx1 2个tikv，xx2 3个tikv, bj1 3个tikv。目前region 副本分布如下：

region 51 副本分布xx1:1个, xx2:2个 ,bj1: 2个

现在想要设置region副本分布为 xx1:2个 ,xx2:2个 ,bj1:1个。参考placement rule官方文档增加了如下规则。
[
{
“group_id”: “test”,
“id”: “xx1”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 2,
“label_constraints”: [
{“key”: “zone”, “op”: “in”, “values”: [“xx1”]}
],
“location_labels”: [ “city”,“zone”,“host”]
},
{
“group_id”: “test”,
“id”: “xx2”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 2,
“label_constraints”: [
{“key”: “zone”, “op”: “in”, “values”: [“xx2”]}
],
“location_labels”: [ “city”,“zone”,“host”]
},
{
“group_id”: “test”,
“id”: “bj1”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 1,
“label_constraints”: [
{“key”: “zone”, “op”: “in”, “values”: [“bj1”]}
],
“location_labels”: [ “city”,“zone”,“host”]
}
]
增加placement rule后，副本数增至8个(总tikv数量)，每个zone内增加了1个副本

想要达到副本分布为 xx1:2个 ,xx2:2个 ,bj1:1个 该如何设置placement-rule？
设置的总副本数是5为什么在上述步骤增加placement-rule后副本数增加至8个？

[yilong (yi888long)]

1. 麻烦帮忙反馈下 region id 51 的 规则

pd-ctl config placement-rules show --region=51

2. 如果可以的话，也反馈下 所有规则

pd-ctl config placement-rules show

3. max-replicas 可以注意下文档
   https://docs.pingcap.com/zh/tidb/v4.0/configure-placement-rules#placement-rules-使用文档
   
   

[h5n1]

新初始化的集群，做其他测试已经destroy了， placement-rule show 还能看见些会话记录信息
» config placement show config
[
{
“group_id”: “pd”,
“id”: “default”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 5,
“location_labels”: [
“city”,
“zone”,
“host”
]
},
{
“group_id”: “test”,
“id”: “bj1”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 1,
“label_constraints”: [
{
“key”: “zone”,
“op”: “in”,
“values”: [
“bj1”
]
}
],
“location_labels”: [
“city”,
“zone”,
“host”
]
},
{
“group_id”: “test”,
“id”: “xx1”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 2,
“label_constraints”: [
{
“key”: “zone”,
“op”: “in”,
“values”: [
“xx1”
]
}
],
“location_labels”: [
“city”,
“zone”,
“host”
]
},
{
“group_id”: “test”,
“id”: “xx2”,
“start_key”: “”,
“end_key”: “”,
“role”: “voter”,
“count”: 2,
“label_constraints”: [
{
“key”: “zone”,
“op”: “in”,
“values”: [
“xx2”
]
}
],
“location_labels”: [
“city”,
“zone”,
“host”
]
}
]

[yilong (yi888long)]

你这个总共是需要 10 个副本，5+1+2+2 =10 ， pd 是个名称，不是指的pd的副本数。 只有 8 个是因为 tikv 只有 8 个吧

[h5n1]

默认default策略是5个，我试过删除报错，我想5副本设置为2+2+1，另外max_repicas参数设置是5.为什么能超过5呢

[nolouch-PingCAP (ShuNing)]

需要使用 group override 的设置，不然规则是叠加起来的，可以看官方文档最上面的图理解一下。

[h5n1]

明白了，那这个最大副本数max_replicas不是一个硬限制吗

[yilong (yi888long)]

你一次回答的贴图看一下吧

[h5n1]

不好意思，光注意看下边了