Memory usage of file versus Database

Hi guys,
I'm writing the server for a Javascript app that has a syncing feature. Files and directories being created and modified by the client need to be synced to the server (the same changes made on the client need to be made on the server, including deletes).

Since every file is on the server, I'm debating the need for a database entry corresponding to each file. The following information needs to be kept on each file/directory for every user:

1. Whether it was deleted or not (since deletes need to be synced to other clients)
2. The timestamp of when every file was last modified (so I know whether the file needs updating by the client or not).

However, I also have to fit under my 80mb memory constraint. Between file storage and database storage, which would be more memory-efficient for this purpose?