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Pi4 slow USB drive fixed

January 13, 2021 — BarryK

I have posted about extreme sluggishness of EasyOS on the Raspberry Pi4, and fixes:

Unfortunately, that is not the end of the story. Bootup is slow, the desktop drive icons are very slow to load, and other drive-related operations are very slow. A bit of online research on Pi forums revealed the cause -- "USB attached SCSI" (CONFIG_UAS) is enabled in the kernel.

UAS makes UAS-enabled SSDs go faster, however, it seems to be broken, even on some supposedly UAS-enabled SSDs. I do recall this issue, and EasyOS kernels for x86_64 PCs have CONFIG_UAS disabled.

I have recompiled the 5.10.4+ kernel for the Pi4, with these changes:

Device Drivers --> USB support
< > USB attached SCSI
General setup --> Preemption model
"Voluntary kernel preemption"
CPU power management --> CPU frequency scaling --> Default CPUFreq governor

Yay, fast bootup, desktop drive icons appear immediately.

My SSD is a 500GB WD Blue SATA, which is pretty mainstream, the kind that many people would buy, so it is the best move to disable UAS. 

Here is the previous post about compiling the 5.10.4+ kernel for the Pi4. That time, I compiled on my Rock64 board, this latest compile was on the Pi4. Previous post: 

Tags: easy