# 可用性测试组

根据优先级和可用性选择一个可用的策略。可用性通过访问一个 URL 来测试，就像自动测试组一样。区别在于降级组只关心可用性，而不关心具体的延迟。定义在前面的策略具有高优先级。

`FallbackGroup = fallback, ProxySOCKS5, ProxySOCKS5TLS`

### 临时覆盖 (Temporary Override)

你可以通过手动选择策略来临时覆盖自动测试的结果。

* 在 Surge Mac 中，你可以在主菜单中对应的组里找到覆盖选项。
* 在 Surge iOS 中，你可以在策略组视图中长按对应策略的菜单找到覆盖选项。

### 参数

#### `interval`: 可选，单位为秒，默认值：600（秒）

决定多久之后丢弃基准测试结果。

#### `timeout`: 可选，单位为秒，默认值：5（秒）

如果在超时时间内未完成，则放弃该策略。


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://surge.mitsea.com/policy-group/fallback.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.