通过Homebrew重装MongoDB（原安装为Homebrew）会丢失现有数据库吗？

Great question—let me walk you through what happens when you reinstall MongoDB via Homebrew, and whether your data is at risk.

Short Answer #

By default, you will NOT lose your existing databases when running brew tap mongodb/brew followed by brew install mongodb-community.

Detailed Breakdown #

Here’s why your data stays safe, plus a few things to watch out for:

• Default data directory: Homebrew-installed MongoDB stores its data in /usr/local/var/mongodb (for Intel Macs) or /opt/homebrew/var/mongodb (for Apple Silicon). Reinstalling only replaces the MongoDB binary files and default configuration files—it does not touch this data directory. If the default config file is overwritten, Homebrew usually backs up your old config with a .bak suffix, so you can restore any customizations if needed.
• Custom data directories: If you modified your MongoDB config to use a non-default data path, that directory is completely untouched by the reinstall process. Just make sure the new MongoDB instance has permissions to access that custom path after reinstalling.
• Pre-reinstall safety step: While data loss is unlikely, it’s always smart to back up your data before making changes. Use the mongodump command to export all your databases to a safe location:

  mongodump --out /path/to/your/backup/folder
  

Recommended Reinstall Steps (to avoid issues) #

1. Stop the running MongoDB service first:

   brew services stop mongodb-community
   

2. Run your reinstall commands:

   brew tap mongodb/brew
   brew install mongodb-community
   

3. Restart the service once the install finishes:

   brew services start mongodb-community
   

After restarting, you should be able to connect to MongoDB and access all your existing databases just like before.

内容的提问来源于stack exchange，提问作者Andrew Einhorn