A remote technician is notified that a LED light for a server's hard drive is red. Which of the following should the technician check to verify RAID functionality?

When addressing a situation where a red LED light indicates a potential issue with a server's hard drive, verifying the RAID functionality is crucial. A file system check is appropriate in this context because it can identify issues related to the integrity of the data stored on the RAID array and ensure that the file system is functioning properly.

File system checks help confirm that the data on the disks is not corrupted and that the file system can properly manage the RAID configuration. Since RAID configurations are designed for redundancy and performance, ensuring that the file system is intact directly relates to the overall success and reliability of the RAID system.

Other options do not directly assess RAID functionality: network-based hardware administration typically addresses connectivity and configuration issues across the network rather than file system integrity; access control lists pertain to permissions and security rather than RAID health; and connectivity via a serial cable would not provide insights into the status of RAID functionality itself. Therefore, performing a file system check is the best choice to verify the RAID operation and ensure that it is functioning as intended.