An older server has performance problems writing files to a RAID array. What should be checked NEXT after no failed drives are found?

In the scenario where an older server is experiencing performance issues when writing files to a RAID array, checking the cache battery is a crucial next step. The cache battery is responsible for maintaining the integrity of the RAID controller's cache memory. When writing data, the RAID controller often uses cache memory to improve performance by temporarily storing write operations before they are committed to disk.

If the cache battery is failing or has failed, the RAID controller may not be able to use the cache effectively, leading to significant slowdowns during write operations. This situation can manifest as performance problems because the data may be written directly to the disks without the benefits of caching, which is usually faster. Therefore, ensuring the cache battery is functioning correctly is essential for optimal RAID performance.

While inspecting other components like the cooling system, hard drive trays, and hard drive cables may also be warranted in a comprehensive diagnosis, they are less directly linked to the immediate performance issues described in the question. The cooling system mainly affects thermal management, which can cause performance throttling if overheated. Meanwhile, the hard drive tray and cables pertain more to physical integrity and connectivity rather than caching functionality.