Iowait issue on Raspberry 4 - 4MB with 5TB SSD

Hi all

I run Umbrel on an Raspbeery Pi 4 with 4MB RAM (with solid Power supply) in combination with a new 5TB SSD (connected with the blue plugins).

Issue: During the “full sync” of Bitcoin almost every minute I got a “Critical CPU_IOWAITING” Warning for approx 10s. After a few hours the IOWAIT sucks >90% of the CPU and the sync stay on hold for hours.

After several days of testing, monitoring I exchange the 5TB SSD with an older 1TB SSD but it didn’t help at all.

What can I do to get rid of this issue?

Thanks for your support and any recommendation.