所以我刚刚将操作系统更新为MacOS 10.15，并且一直在尝试重新启动mongodb服务。通常，我通过键入mongod来完成此操作。但我一直遇到错误，
2019-10-18T16:37:47.573-0400 I CONTROL [initandlisten] MongoDB starting : pid=90637 port=27017 dbpath=/data/db 64-bit host=Hrishikeshs-MacBook-Pro.local
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] db version v3.6.8
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] git version: 6bc9ed599c3fa164703346a22bad17e33fa913e4
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] OpenSSL version: OpenSSL 1.0.2r 26 Feb 2019
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] allocator: system
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] modules: none
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] build environment:
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] distarch: x86_64
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] target_arch: x86_64
2019-10-18T16:37:47.574-0400 I CONTROL [initandlisten] options: {}
2019-10-18T16:37:47.577-0400 I STORAGE [initandlisten] exception in initAndListen: NonExistentPath: Data directory /data/db not found., terminating
2019-10-18T16:37:47.577-0400 I CONTROL [initandlisten] now exiting
2019-10-18T16:37:47.577-0400 I CONTROL [initandlisten] shutting down with code:100
就像它说的那样，它没有/data/db。当我做sudo mkdir -p /data/db时，出现错误消息，mkdir: /data/db: Read-only file system
我在某处读到新操作系统上的根文件夹不再可写。有人可以告诉我如何启动我的mongodb服务吗？谢谢。