RAID drive self-checks interfere with my work too often

This is a wonderful feature of "energy saver", where MacOS spins down drives all the time. On a RAID volume, it takes longer for them to spin right back up, as there are 4 drives or more.

Change your energy saving settings (likely under screen lock). I would set screen lock to never. that should take care of this, elese you need a third party utility like Amphetamine, or caffeine to keep the drives awake.

SoftRAID does not affect sleep settings at all.

I had my Mac expert log in today and check this -- I have a MacBool M1 Pro.  OS 15.7.3.  The setting is (and has been forever) to keep hard drives awake.  He says Caffeine and Amphetamine won't do anything that the setting I have does.

So maybe that isn't the problem.  What happens is every few minutes (even when the computer is asleep) the 4 green lights on the Raid housing start bouncing around -- some holding for a few seconds then all of them flashing -- I could try to note the sequence but it is complicated.  It just did it while I was typing this with no problem, but if I am using Photoshop, and maybe Lightroom, I get the spinning beachball until they are finished flashing.  (PS and LR are closed just now.)  

a) what is causing the lights to flash?  

b) Why does it stop Photoshop (and Lightroom, I think) with a spinning beachball?  I'm not sure about things like MS Office but I don't think it is bothered when they flash.

c) What can be done to stop the interference (the beachball pause) -- it is driving me NUTS!

If it matters, the Raid housing is plugged into a Thunderbolt Dock.

@dianemiller 

MacOS has multiple busgs in sleep/hibernate/DarkWake areas.
try this terminal command to set sleep to 0. Its "stronger" than the UI settings.
sudo pmset -a sleep 0

Why does this cause Photoshop or Lightroom to pause with a spinning beachball?
Applications such as Photoshop and Lightroom frequently access disk resources even when they appear idle. They use scratch files, memory-mapped files, and metadata queries that are sensitive to storage latency. When macOS performs one of these Thunderbolt or NVMe power or status checks, I/O to the RAID can briefly stall. During that stall, applications waiting on disk access block, which results in the spinning beachball until the operation completes.
Applications that rely less on continuous disk access, such as Microsoft Office, may not be affected or may mask the delay.

What can be done to reduce or stop the interference?
There is currently no way to fully disable these Thunderbolt power-management events in software. However, the following steps can reduce their impact:
Avoid using the RAID as a scratch disk for Photoshop or Lightroom; use the internal SSD instead.

Even while you’re typing or working in Photoshop:

macOS periodically:
revalidates Thunderbolt links
queries NVMe device state
performs power or link-state housekeeping
This can briefly stall I/O to the enclosure
Apps waiting on disk I/O block → beachball
From macOS’s perspective, this is not “sleep”:

The CPU is running
The UI is responsive
Only the storage path stalls briefly

Even during active use, macOS performs periodic Thunderbolt and NVMe power-management operations that are independent of system sleep. Utilities like Caffeine prevent the system from sleeping but do not stop these hardware-level events. When they occur, disk I/O can briefly stall, which causes storage-intensive applications like Photoshop to pause.

OK, thanks.  I would never assign the RAID as a scratch disk.  Guess I just have to keep shutting it down when I'm working with PS on files on the Mac SSD, and copy files to the Mac drive when I need to work on them.

@dianemiller 

And hope this issue gets resolved.

That sounds like a very faint hope.  Is this something that is not an issue with Windows?

@dianemiller 

Not that I know of, Windows does not have the tightly integrated power management that the mac has, so while less energy efficient, less likely to have this kind of specific issue.