无论是剩余内部硬盘空间小的问题还是个人喜好，外部硬盘在很多方面都很有用。考虑到这一点，在Linux中使用外部USB硬盘作为/home挂载是安全的吗？今天的超级用户问答帖子讨论了这个问题，以帮助好奇的读者。

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

照片由Karen（Flickr）提供。

问题

超级用户读者misha256想知道在Linux中使用外置USB硬盘作为/home挂载是否安全：

I am getting ready to give Linux Mint a whirl. As I understand it, /home is where the user’s content like documents, downloads, and media will be stored. Because my SSD hard-drive is **all, I would like to use an external USB hard-drive for /home. This raises a couple of questi***:

1. Is there anything inherently wrong or bad in doing this?
2. Will it be reasonably safe and reliable compared to using an internal SATA hard-drive?

在Linux中，使用外部USB硬盘作为/home挂载是否安全？

答案

超级用户贡献者acevalin和Hennes为我们提供了答案。首先，acejavelin：

Assuming that you have a quality USB port, cable, and external hard-drive, it should be as safe and reliable as using an internal drive, especially if you have USB 3.0. If you are using USB 2.0, then you will likely see some very noticeable performance degradation.

接着是海恩斯的回答：

There is no problem with putting /home on an external hard-drive assuming that:

1. Your external hard-drive does not get unplugged mid operation (neither Windows nor Linux likes that). Windows ships with a default setting which makes access a lot slower but safer, which means do not unplug it while in use.
2. Speed will be slower than a direct connection to the SATA or SAS Bus. How much slower depends on the connection and for many things even USB 2.0 (at ~30MB/sec) might be fast enough (i.e. playing MP3’s and movies, reading config files, etc.).
3. This does assume that you power up the external hard-drive before you boot the laptop (mounting will fail otherwise).
4. It ignores any potential USB driver bugs (easy enough to test though).

Note that there are lots of stories about external hard-drives being less reliable. I have no idea if this is true or if it is merely a result of having droppable devices that get lugged around in backpacks, going from cold (outside) to hot and humid inside (maybe a bit of both).

Do not get a WD Green Drive as an external hard-drive because they tend to park a lot. They are good for power usage if the hard-drive is used as archive storage and then allowed to spin down when not in use. When in active use (either in Windows, Linux, or any other operating system), you might get a hard-drive that spins down every minute, then spins back up, and down, and up, and down, etc. This tends to wear out the hard-drive and waiting on it to spin back up adds delays to the operating system.

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