I noticed my iPhone’s System Data had somehow grown to 25GB, so I did a bit of digging and ended up freeing about 8GB.
The first thing that helped was a force restart: press Volume Up, release, press Volume Down, release, then hold the Power button until the Apple logo appears.
看了下我的 iPhone 的系统数据居然有 25G，找了找方法清理了 8 个G，有需要的小伙伴也可以试试。
首先强制重启 iPhone，音量 + → 松开，音量 − → 松开，然后长按电源键，直到出现苹果 Logo，等一会儿重启后去查看你会发现了少了几个G。
然后在设置 → Apple ID → iCloud → iCloud