Different tools are available for HDD diagnostics:

1. Dell Online Diagnostics: Can be run in the Operating system to test different components.

2. Dell 32-Bit Diagnostics: Requires a reboot of the server.

3. Embedded Hardware Diagnostics: From generation 11 and upwards, requires a reboot of the server.

4. Performance diagnostic tools and methods: www.dell.com/support/article/HOW10140 

For more technical content, you can refer to our online Enterprise Knowledge base.