Handling failed requests

<!--HTML-->The CERN Tape Archive (CTA) is a vital system for storing and retrieving data at CERN. However, the reliability of the CTA system can be impacted by various factors, including hardware failures, software bugs, and network connectivity issues. To ensure the continued availability of the stored data, it is critical to have robust mechanisms in place for handling failed requests. This talk will cover the strategies employed by the CTA team at CERN for managing failed requests in the system. These include techniques such as automatic retries, requests classification and file reinjection. By implementing these measures, the CTA team ensures the majority of failed files are archived to tape without user intervention during incidents and in normal operations mode.