The default storage adaptor may, in some cases, serve all of your application's persistence needs. TLCachingFileStorageAdaptor uses an instance of TLMultiFileDatabase to manage file-based persistence of TLRegisteredUser objects. Each user object is read and written individually to its own file.
Numbered versions of each user file are maintained. By default, two versions are retained for each user. The files are named with the userId, the base36-encoded username and the base36-encoded email address. This allows TLCachingFileStorageAdaptor to use the file system's wildcarding support to select files by userId, username, or email address. Base-36 encoding is used to ensure that no characters disallowed by the file system appear in the filenames.
The default database directory created in the Pharo Contents/Resources directory is named app-nameUserDb where app-name is the value passed as the TLLoginComponent class>>#appName: during initialization.
TLCachingFileStorageAdaptor caches (by default) the 100 most recently accessed user objects and all usernames and associated userIds. File writes are queued to a background writer process to avoid delaying response to the user. Files are spread across an automatically-created sub-directory tree to avoid the performance penalty that occurs when a very large number of files is present in a single directory. TLCachingFileStorageAdaptor has been tested with 100,000 users and performs well with that user population.