Now these are availability and unavailability.

现在，这些是有效性和无效性。

youdao

Unavailability of the data source, for example when a server is down.

数据源不可用，如服务器停机时。

youdao

Unavailability of the data source, for example when a server is down.

数据源不可用，如服务器停机时。

youdao