Troubleshooting tools

Do you guys know what are (if there’s any) tools available in this crappy OS where I can determine what process is reading/writing on my disks?
Every night my fans go full speed and top won’t give me any hint of what’s happening. Tools like iotop or lsof aren’t available.
I would love to know who’s the ■■■■■ that made the decision to remove everything useful from the OS. Even tcpdump is gone.

Hello,

Please refer to the following KBA article: Possible My Cloud Dashboard Fan Speed and Drive Temperatures

Hi Chris, that information is already available through fan_control

Screenshot from 2021-06-19 13-26-09

The fact that my fan goes on when my NAS is supposedly idle is the problem, and I’m looking for tools that give me the cause.
The possible causes are, high CPU usage, which we can use top to check that, or the disks are active and generating heat, which is the probable cause, but WD removed the tools that could tell me what’s being done on my disks.
What’s the point of having SSH access if WD OS has fewer tools than a $10 router?