Firstly, according to the description of official documents, the configuration file is created, the database path is modified, and the configuration filemongo.configThe content is as follows:

systemLog:
 destination: file
 path: I:\mongodb_data\log\mongod.log
 logAppend: false
 storage:
 dbPath: I:\mongodb_data\db
 net:
 port: 27017
 bindIp: 127.0.0.1

Then, mongodb’s service was customized with the following command:

mongod --config "C:\\Program Files\\MongoDB\\Server\\3.6\\mongo.config" --install

Then the mongdb service was restarted, but after mongod was opened, it was found that the database path was still on disk C, as follows:

C:\Program Files\MongoDB\Server\3.6\bin>mongod
 2018-03-26T23:33:52.760-0700 I CONTROL  [initandlisten] MongoDB starting : pid=29408 port=27017 dbpath=C:\data\db\ 64-bit host=LAPTOP-5EHTU72R
 2018-03-26T23:33:52.760-0700 I CONTROL  [initandlisten] targetMinOS: Windows 7/Windows Server 2008 R2
 2018-03-26T23:33:52.761-0700 I CONTROL  [initandlisten] db version v3.6.3
 2018-03-26T23:33:52.763-0700 I CONTROL  [initandlisten] git version: 9586e557d54ef70f9ca4b43c26892cd55257e1a5
 2018-03-26T23:33:52.764-0700 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.1u-fips  22 Sep 2016
 2018-03-26T23:33:52.766-0700 I CONTROL  [initandlisten] allocator: tcmalloc
 2018-03-26T23:33:52.767-0700 I CONTROL  [initandlisten] modules: none
 2018-03-26T23:33:52.769-0700 I CONTROL  [initandlisten] build environment:
 2018-03-26T23:33:52.771-0700 I CONTROL  [initandlisten]     distmod: 2008plus-ssl
 2018-03-26T23:33:52.773-0700 I CONTROL  [initandlisten]     distarch: x86_64
 2018-03-26T23:33:52.774-0700 I CONTROL  [initandlisten]     target_arch: x86_64
 2018-03-26T23:33:52.776-0700 I CONTROL  [initandlisten] options: {}
 2018-03-26T23:33:52.778-0700 I STORAGE  [initandlisten] exception in initAndListen: NonExistentPath: Data directory C:\data\db\ not found., terminating
 2018-03-26T23:33:52.779-0700 I CONTROL  [initandlisten] now exiting
 2018-03-26T23:33:52.782-0700 I CONTROL  [initandlisten] shutting down with code:100

Why is the configuration file invalid? I did it completely according to official documents.