Using USB 3.0 1TB USB HDD with Series 9

[Members_ACI0NpP]

To enable using Timeshift and recording, I've attached a USB 3.0 HDD to my Series 9 TV, it has a 1TB capacity. 

Even though I have formatted the drive, I get the message... use a higher speed external drive. But it doesn't say what speed I should have as minimum. 

Does anyone know what I should be using? 

Thanks

[AndrewL]

@Members_ACI0NpP: The user manual states the following: "A USB hard drive with a speed of 5,400 rpm or above is recommended. However, RAID-type USB hard drives and USB memory sticks are not supported." I hope this helps. 

[Members_ACI0NpP]

Thank you.