

DO NOT USE REGULAR PCI-E CARDS THAT ADD SATA PORTS. Many are unreliable. What you want is called a SAS Host Bus Adapter card and you want to get one that’s pre-flashed in IT mode.
The LSI 9207 is a good choice.
Make sure you get the correct SAS to SATA cables and you are set. You can add 8 to 16 SATA drives with a single, high speed, and reliable card.
Honestly with the speed of that server it could just be scrapping bots overloading it.