Hi Rita,
When you use the command-line task with the --repository option, you are telling AtoM to delete every description linked to the repository whose slug you provide. If you have many large hierarchies linked to that repository, it is possible that either the available system memory is exhausted before the task completes, or the timeout limits set in your PHP execution limits are reached before the task completes.
Instead, you might try just deleting one fonds / collection at a time. For example, if the description you want to delete has a slug of "my-example-fonds", you can pass the delete command like so:
- php symfony tools:delete-description my-example-fonds
You can also try adjusting your PHP execution limits. See this page for suggestions:
You might want to increase values like the max_execution_limit and the memory_limit. Remember to restart PHP-FPM after making changes!
Finally, if you are able to allocate more memory to your AtoM installation, this might help as well.
If none of that works, then you might try deleting a very large fonds in parts. For example, delete a sub-series first, then the parent series, etc. Once you have deleted some of the lower-level records, you should be able to delete the entire fonds.
Good luck!