TiKV宕机无限OOM起不来，如何正确恢复

tidb 5.0.3

因为写入并发过大，tikv负载较高，有一台宕机了，且一直OOM起不来，pd store显示disconnect，且该store上有大量leader region，现在应该如何恢复正常

看一下 TiKV 重启的 OOM 对应的 log 里面有记录 slow query 的记录，另外通过 dashboard 的 slow query 和 热力图 定位热点问题看看。一般都是有热点业务查询导致，所以需要进一步看一下 slow query。

不是query导致的，是高并发写入造成的，这个不是关键，关键是一个tikv down了，现在怎么恢复，这是现在最紧要的

看一下 TiKV 启动 log 报错 ？

tikv.tar.gz (3.5 MB)
tikv1.tar.gz (18.8 MB)

@Lucien 日志显示是这两个ERROR，我从监控和top中看到的是 tikv启动，内存飙升，近100%后宕机重启，现在pending和down了太多region了，我们想赶紧先能正常起来

尝试了下这个，也不管用，还是OOM

现在集群应该是可用状态，如果担心集群的可用性问题，建议优先进行 TiKV 节点扩容操作。现在是只有 91 节点出现 oom 吗 ？是虚拟机 ？还是物理机 ？机器内存配置是多大 ？

只有这个节点OOM，物理机，16G内存，集群是可用状态，但是还有一些在途的读取写入任务，担心再有节点挂掉，集群就完了
这个节点刚刚宕机重启，还好起来了，起不来，这个集群就GG了。。。

现在 OOM 的 91 节点还是无法启动吗？看日志只有 12 点有 welcome ，但是没有最近的状态。

服务器有时差，就是最近的，还是OOM无法启动，我看了下刚才又挂了一个tikv，虽然重启起来了，第三个tikv目前cpu也飙升，我感觉这个集群现在很危险，我直接–force，再改端口扩回来，先保证3个节点正常？

可以的，不过 16 GB 的确有点小，可以扩到 32 GB 内存。

嗯嗯，我们准备升级配置，先把副本补回来

我把pd配置能调大的都调大了，感觉调度好慢啊，12个小时就调度了这些，这还是集群一个任务都没跑的情况下，把这些参数调很大了，cpu，内存，io都还很小，感觉这些参数没起到啥作用。。

{
“replication”: {
“enable-placement-rules”: “true”,
“isolation-level”: “”,
“location-labels”: “host”,
“max-replicas”: 3,
“strictly-match-label”: “false”
},
“schedule”: {
“enable-cross-table-merge”: “true”,
“enable-debug-metrics”: “false”,
“enable-joint-consensus”: “true”,
“enable-location-replacement”: “true”,
“enable-make-up-replica”: “true”,
“enable-one-way-merge”: “false”,
“enable-remove-down-replica”: “true”,
“enable-remove-extra-replica”: “true”,
“enable-replace-offline-replica”: “true”,
“high-space-ratio”: 0.7,
“hot-region-cache-hits-threshold”: 3,
“hot-region-schedule-limit”: 256,
“leader-schedule-limit”: 400,
“leader-schedule-policy”: “count”,
“low-space-ratio”: 0.8,
“max-merge-region-keys”: 200000,
“max-merge-region-size”: 20,
“max-pending-peer-count”: 300,
“max-snapshot-count”: 30,
“max-store-down-time”: “30m0s”,
“merge-schedule-limit”: 80,
“patrol-region-interval”: “100ms”,
“region-schedule-limit”: 2048,
“region-score-formula-version”: “v2”,
“replica-schedule-limit”: 1280,
“scheduler-max-waiting-operator”: 40,
“split-merge-interval”: “1h0m0s”,
“store-limit-mode”: “manual”,
“tolerant-size-ratio”: 0
}
}

store limit 有调整吗？没有的话把 store limit 全部调大点，参考：
https://docs.pingcap.com/zh/tidb/v5.0/configure-store-limit

请问是什么命令用force来启动？

请问这个是什么命令加force 来启动？谢谢

不是force 启动， 我是问 可不可以 --force强制下线，再改端口扩回来，会不会丢数据

在补副本的过程中，tikv一直在尝试连接那两个下线的tikv节点，导致tikv目前不提供服务了，是不是有region丢失了，可是3副本，也没强制下线，我是先补的副本，为什么会有region不可用了呢，查了下没有 无leader的region

1.现在各节点上磁盘空间充足吗？最上面的监控面板中提示存在 lowspace 的 store ，有可能是磁盘空间不足导致调度一直没有完成，而且机器内存只有 16G ，低于标准部署要求，建议直接在一台新的机器上扩容 tikv 节点；
2.通过 pd-ctl 看下两个处于下线状态的 store ，看下 region_count 和 leader_count 有无减少；
3.检查下目前副本数小于 3 和小于 2 的 region 有多少个，如果是正常下线一般不会导致 region 数据丢失。

1.磁盘都很充足，lowspace的是监控数据问题，

2.27节点的不减少(这个之前用了–force强制踢出去了，实际的数据已经没了)，91是有减少的
3.没有小于3的，jian监控显示也没有miss region，但是 用程序读数据，就会报region不可用了

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