November 2021
Intermediate to advanced
410 pages
12h 1m
Chinese
Content preview from MongoDB权威指南（第3版）
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部署
MongoDB
｜
371
然而，
MongoDB
偶尔会在需要排序数据的操作（创建索引或进行排序操作）中使用交换
空间。
MongoDB
会尽量不为这些类型的操作使用太多内存
，但如果同时执行了许多这样
的操作，那么可能会被迫使用交换空间。
如果应用程序让
MongoDB
使用了交换空间
，则应该考虑重新设计应用程序或减少服务器
上的负载。
21.1.6
文件系统
在
Linux
系统中，对于使用
WiredTiger
存储引擎的数据卷，建议只使用
XFS
文件系统。也
可以将
ext4
文件系统与
W
iredTiger
一起使用，但是要注意其中一些已知的性能问题（具体
来说，
W
iredTiger
创建检查点的时候可能会卡住）。
在
W
indows
系统中，可以使用
NTFS
或
FAT
。
不要使用直接挂载的
NFS
（
network file storage
）文件系统作为
MongoDB
的
存储。有些客户端版本会隐瞒数据刷新的情况，随机重新挂载并刷新页面缓
存，并且不支持排他文件锁。使用
NFS
会导致日志损坏，应该不惜一切代价
避免。
24.2
虚拟化
虚拟化是获取廉价硬件和快速扩展的好方法。然而，它也存在一些缺点，特别是不可预测
的网络和磁盘
I/O
情况。本节会讨论与虚拟化相关的问题。
24.2.1
内存过度分配
Linux
内核的内存过度分配（
memory overcommit
）设置可以用来控制当进程向操作系统请
求过多内存时应该采取的策略。根据这一设置，内核可能会为进程分配内存，即使这些内
存实际上是不可用的（希望在进程需要的时候它会变得可用）。这被称为
过度分配 ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.