FortiAnalizer Historical logs Problem

Hi, I have a problem with the display of historical logs, the real time works fine but when i try to display the logs for example of the last 30 minutos it show me "no records found", but the logs has been saved and I have logs from moths ago

The problem that I see right now is that the CPU is always at 100%

I execute the command "execute top" and it show me next output, according to this the part of wa is consuming a lot of CPU,     i´ve read some documentation and this part it means " waiting por I/O" but I don´t now what it means

Cpu(s): 30.5%us,  5.3%sy,  0.0%ni,  0.0%id, 63.2%wa,  0.0%hi,  1.0%si,  0.0%st

Version: v5.2.7

HElp

Regards