There are various maintenance tasks which can be performed to maintain a healthy TYPO3 installation with the file abstraction layer.

Scheduler tasks

Two base tasks provided by the scheduler are related to the file abstraction layer.

File abstraction layer: Update storage index

This task goes through a storage and makes sure that each file is properly indexed. If files are only manipulated via the TYPO3 backend, they are always indexed. However, if files are added by other means (for example, FTP), or if some storages are based on drivers accessing remote systems, it is essential to run this task regularly so that the TYPO3 installation knows about all the existing files and can make them available to users.

This task is defined per storage.

File abstraction layer: Extract metadata in storage

This task goes through all files in a storage and updates their metadata. Again, this is especially important when files can be manipulated by other means or actually reside on external systems.

This task is defined per storage.

Processed files

If you change some graphics-related settings, it may be necessary to force a regeneration of all processed files. This can be achieved by deleting all existing processed files in Admin Tools > Maintenance > Remove Temporary Assets.

Removing all processed files in the Maintenance Tool

Here you can choose to delete all files in fileadmin/_processed_/

This cleanup is also a good idea if you have been accumulating files for a long time. Many of them may be obsolete.

After flushing page cache, it is a good idea to warmup the page cache. Generating the pages for the first time may take longer than usual because the processed files need to be regenerated. There is currently no Core functionality to warmup the page cache for all pages, but there are a number of extensions which provide this functionality. Alternatively, one can use the sitemap and a tool such as wget for this.

Also, deleting processed files while editors are active is not ideal. Preferably, lock the TYPO3 backend before you remove the processed files.