是什么导致 mongodb replset 这么慢？答案

【问题标题】：What can cause mongodb replset to be so slow?是什么导致 mongodb replset 这么慢？
【发布时间】：2023-03-11 03:14:01
【问题描述】：

这是第一次同步到主节点：

2017-03-03T02:26:22.035+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 283940/5543302 5% (documents copied)
2017-03-03T02:36:17.984+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 564884/5543302 10% (documents copied)
2017-03-03T02:48:31.792+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 849813/5543302 15% (documents copied)
2017-03-03T03:02:14.751+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 1138030/5543302 20% (documents copied)
2017-03-03T03:14:10.938+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 1474370/5543302 26% (documents copied)
2017-03-03T03:32:53.645+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 1846885/5543302 33% (documents copied)
2017-03-03T03:46:50.211+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 2207922/5543302 39% (documents copied)
2017-03-03T03:56:41.963+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 2568851/5543302 46% (documents copied)
2017-03-03T04:08:13.513+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 2921563/5543302 52% (documents copied)
2017-03-03T04:27:33.926+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 3230454/5543302 58% (documents copied)
2017-03-03T05:09:17.002+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 3408499/5543302 61% (documents copied)
2017-03-03T05:27:33.817+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 3531029/5543302 63% (documents copied)
2017-03-03T06:12:44.765+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 3747209/5543302 67% (documents copied)
2017-03-03T06:49:28.263+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 3894147/5543302 70% (documents copied)
2017-03-03T07:46:30.452+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 4001247/5543302 72% (documents copied)
2017-03-03T08:06:56.895+0100 I -        [repl writer worker 3]   prodbase.offer collection clone progress: 4108649/5543302 74% (documents copied)

所有服务器都在同一个数据中心，它们之间的速度为 250 Mbit/s。

【问题讨论】：

你检查过你的磁盘IO吗？

标签： mongodb replication database-replication replicaset

【解决方案1】：

建议：移至 3.4.x

初始同步的重大改进

否则，一切都取决于您在主节点上拥有多少数据

避免这种情况的另一种解决方案是

备份您的主节点
将主要恢复到您的次要
配置并开始复制

【讨论】：

我们在所有实例上都有 3.4.1。我知道复制目录可能会快得多，但没想到原生同步这么慢。
您的数据有多大？在我们的案例中，我们有大约 10Gb 的数据，初始同步时间不到 45 秒到 1 分钟。在 800KM 外的节点上，需要 2-3 分钟。
该集合的大小为 55Gb（WiredTiger 压缩为 20Gb）。