You should make a copy of the disk as a backup.

你应该将磁盘复制一个备份。

《牛津词典》

Although many of these storage media have high capacity, a backup tool with compression capabilities is a big plus, eliminating the inconvenience of multiple disks or large uploads.

尽管这些存储介质中有许多具有高容量，但具有压缩能力的备份工具是一大优势，它消除了多个磁盘或大型上传的不便。

youdao

While the terror group established a large, secretive external operations wing bent on attacking the West, it has also cultivated a backup strategy of enabling and inspiring attacks by individuals.

虽然这个恐怖组织建立了一个庞大的、秘密的外部行动部门，致力于攻击西方，但它也形成了一种支持和鼓励个人发动袭击的后备战略。

youdao

In the late 1980s, Jon was hired as a backup singer for pop superstar Gloria Estefan.

VOA: standard.2010.04.02

You really need that because if you have only one copy of something, you don't have a backup; so, you can store the one copy separately.

你真的很需要这项发明,因为要是你只有一份的话，你就没有备份;,这样的话，你就可以将副本单独留存。

耶鲁公开课 - 金融市场课程节选

So it's like a backup.

所以，这就像是备用。

关于大学申请 - SpeakingMax英语口语达人

Maybe it'll be broadband, but then there's a backup for 3G connection or 4G, right?

ENGADGET: blogger-avatar

That radio you refer to is actually a backup plan that is almost never used.

FORBES: Lessons From Uber: Why Innovation And Regulation Don't Mix

"I had been with the Cowboys, and everything was first-class, " says Leamon Hall, a backup quarterback.

WSJ: Remembering the Late, Great USFL