External drives continually sleeping and spinning up in M2 Pro Mac mini

[gilby101]

I have set everything I could to prevent sleeping of system and hard drives, multiple times, including after the SMC reset. In particular, I disabled the option to sleep hard drives when possible.

Which makes no difference if it is the firmware in the drive which is causing the drive to do some form of "sleep". I know my WD external drives park their heads after 7 seconds no activity. macOS system settings make no difference to this. Your drives may be doing something similar.

My solution is to run a background process (python script) which writes to the disks every 6 seconds. This little app is similar http://jon.stovell.info/software/keep-drive-spinning/. You need to adjust it to how soon your drives do some form of "sleep".

 

[Fishrrman]

I don't know if this suggestion will help, but it's worth trying and it's FREE.

Download this little utility named "Semulov":

GitHub - kainjow/Semulov: Access mounted and unmounted volumes from the menubar

Access mounted and unmounted volumes from the menubar - kainjow/Semulov

github.com

(look on the right side for "releases", then click "latest" to download it)

It's as "easy-as-pie" to understand and use.
Semulov adds an icon to your right side menu bar.
You can use it to dismount/mount drives and volumes.

I'm wondering if this could solve the problem of drives periodically spinning down and then "automatically" spinning up again?
The idea is to use Semulov to dismount them, and see if they STAY dismounted until you need to access them again. Then, just click on them to "re-mount" them and spin them back up.

I suggest you try this.
Would be interested in hearing if it helped ... or not.

Personal experience:
I have numerous external drives, but I keep ALL of them disconnected (or in the case of my cloned backup drive, connected but powered off) all the time.

I only connect a drive when I need to access it. When I'm done, I dismount and physically disconnect it.

That's "what works" for me.
(I realize others' needs may be different)

 

[davebot 0.9]

Hey Fishrrman, Semulov looks cool. I'll keep that in mind.

gilby, I bet you're right. I haven't been able to find confirmation, but I suspected that either the individual drives or the enclosure's controller had some kind of 'sleep' feature. What surprised me was that, in this mode, the drives are in perfect sync, with the lights pulsing in unison.

But I don't want to keep pinging the drives to be 'awake'. I want the opposite: I want the system to stop trying to access them for events that are unrelated. EVERY TIME I load a new URL in Safari, the drives wake up. Safari doesn't need any files on those old system drives. Also, when I launch a new app, that also spins up these drives. But not the other two external drives -- just these two former start-up drives in that Mercury Elite Dual enclosure. Perhaps when I replace the drives with generic drives for Time Machine, this behavior will end. First, I have to setup my new drives that will allow me to archive the files from these two troublemakers.

I've unmounted the drives. Now loading a new URL in Safari works without spinning up any external drives.

I just removed the old cable and replaced it with a USB-B to USB-C cable to the Mac mini. Now to test...

Launching an app (Scapple, this time) still causes the drives to spin up. Loading a new URL in Safari still causes the drives to spin up. Could there be metadata somewhere that causes these drives to be treated differently?

 

[gilby101]

EVERY TIME I load a new URL in Safari, the drives wake up. Safari doesn't need any files on those old system drives. Also, when I launch a new app, that also spins up these drives.

I had not properly appreciated this. Now have no idea what is going on!

Best I can do is to suggest you monitor all file system activity on your system to see what is accessing the disks. For this I use FSMonitor which has a 14 day trial. As you might expect it captures lots of activity, so just run a capture for a shot period when, for example, you open a new Safari URL. The Filter button help to reduce the clutter. Then you should see what files are being opened on the disks and which process is doing it. Might give you some clues.

 

[davebot 0.9]

OK. I tried FSMonitor. I was scandalized by the number of files hit by just loading another website and launching an app. But there was nothing involving the two old disks.

Then I started wondering about iStat Menus. I disabled the login item for that, and restarted. Since then, the disks have not been sleeping. I then re-enabled iStat Menus and restarted. Still the disks are not sleeping. I don't understand. Everything seems really normal now. I did find settings in iStat Menus for selecting the disks I want monitored, and my two troublemakers are both selected. I was going to de-select them, but I'm still waiting to see if they will go into sleep mode as they did before.

So the behavior has changed, after running FSMonitor and disabling and enabling iStat Menus. I can't see that I have changed anything...

The real test will be to swap in the two new HDDs. But I need to get some time this week to figure out what files I need to archive from the old drives, and I need to set up my new SSDs in their case so I have something to save the files to. Soon!

 

[gilby101]

Then I started wondering about iStat Menus.

Good thought. The disk monitoring keeps on discovering how much free space there is on each drive. (The issue I had with iStat Menus was how disk monitoring creates a vast number of entries in the unified log.). I do wonder if completely uninstalling iStat Menus might make a difference for you.

Don't be too alarmed about what FSMonitor shows you. The file system is very busy even when you are doing nothing!

 

[davebot 0.9]

Aw, nuts. Now it's sleeping and spinning up just as it did before. Turning off the disk monitor feature in iStats Menus didn't help.

 

[Fishrrman]

OP wrote:
"Aw, nuts. Now it's sleeping and spinning up just as it did before. Turning off the disk monitor feature in iStats Menus didn't help."

Gee... why don't you just TRY the little "Semulov" utility I mentioned above in reply 27?

 

[davebot 0.9]

Thanks Fishrrman. Just my personal preference -- for my use case I would rather not have the extra steps of mounting / unmounting, even though they are easy. I'm sure it would work.

There's an underlying issue I want to understand: why does opening a new URL in Safari (but not Firefox) or launching another app cause my system to wait until it pings a drive in that external case? That just seems goofy.

 

[name99]

Thanks Fishrrman. Just my personal preference -- for my use case I would rather not have the extra steps of mounting / unmounting, even though they are easy. I'm sure it would work.

There's an underlying issue I want to understand: why does opening a new URL in Safari (but not Firefox) or launching another app cause my system to wait until it pings a drive in that external case? That just seems goofy.

There appears to be a bug in the Mac file system code where at least some paths through the code route through a "read something from every disk" stage. This is clearly a terrible design decision (and I'm sure it's not designed, per se, probably a nasty byproduct of something else important).

My GUESS is that:
- Apple are aware of this (along with multiple similar such bugs, eg the way Disk Utility can hang, for who knows what reason, while trying to access external drives; or multiple serialization points within the file system code even when different drives are involved)
- at some point everything file system related is going to be moved to a separate process operating outside the kernel (think FUSE crossed with User-space Networking)
- and so fixing all these sorts of issues with external drives has been relegated to getting the new design correct, and having this all fall out of a proper design.

 

[davebot 0.9]

There appears to be a bug in the Mac file system code where at least some paths through the code route through a "read something from every disk" stage. This is clearly a terrible design decision (and I'm sure it's not designed, per se, probably a nasty byproduct of something else important).

 

[davebot 0.9]

Rethinking! I think I'll try the Semulov utility, as Fishrrman suggeested. I'm getting annoyed that when I reply to email messages, the reply has to wait a second or two for my external drives to spin up. Good grief.

 

[daveafrank]

Following up on this since I had similar issues with the OWC Mercury Elite Dual. Talked to customer service and after a half hour of back and forth I think we found a solution(without using Amphetamine). Despite the system setting to never put disks asleep, the tech told me that sometimes that setting doesn't take and you need to change it in the terminal. Just type in sudo pmset -a disksleep 0 and restart. It worked on one computer so far...hoping it does on my work computer as well.

 

[davebot 0.9]

Good going, daveafrank!

I haven't thought about this issue recently because it went away after I put my new drives in the enclosure. They are formatted for TimeMachine. The best thing is that my system does not seem to pause most operations to wait for a ping to those drives to be acknowledged. Perhaps I will want to get in and make sure Sophos ignores those drives, as well as Spotlight. I also need to run the update to the new operating system. "More fun," as one of my colleagues says. But things seem to be Just Working now.

 

[GeordieAl]

Just wondering if anyone has had any luck finding a permanent solution to external drives spinning up and down constantly? I had this issue with an M1 Mac Studio last year - I had several external drives connected via USB hub and they would constantly spin down then up. I was able to fix the issue on the M1 studio using the pmset -a disksleep 0 and also removing the com.apple.powermanagement plist files and doing a reboot.

This week I've upgraded to a M2 Studio and the disks spinning up and down constantly is back to haunt me... I've tried the solutions I used on the M1 Mac Studio but they haven't worked this time. I literally unplugged the hub from the M1 studio and plugged it into the M2 Studio and went from the calm of the drives constantly spinning to the sound of them spinning up and down every 30 seconds.

I've tried the hub in different ports on the Mac - USB A and C, I've disconnected and reconnected other devices but nothing seems to work. It's driving me crazy!

 

[exon]

I've had this exact same problem for some time (i.e. several OS versions) on my 2019 iMac (Intel i5) using a retail boxed LaCie d2 Professional external drive connected to USB, as well as an older drive in a generic USB external case. Drives spin up/down every few minutes until I eject and unplug. I don't want to derail the thread, just wanted to point out that it may not be an Apple Silicon or an issue with custom built external drives.

 

[Rusted Eyes]

I want to thank Herbert7265 for his suggestion regarding Spotlight. Although I have a different 4-bay enclosure, I also had the exact same issue as the OP and had read various threads about it. Nothing I found through them ever worked UNTIL NOW! Herbert, you are the Oracle! 😇

 

[WilliamG]

Sorry for the pseudo-resurrection (it's not that old, I suppose). I have sort of an alternative issue where I can't get the disks to actually spin down. They just stay spinning the whole time, 24/7. OWC Thunderbay 4s. Not sure how to address that...

Mac mini M2 Pro.

 

[uller6]

It's amazing how much harder it is to find stuff on your own hard drive then it used to be in OS 9. Even if you know the exact file name, half your hard drive shows up for any search, with exact matches appearing for an instant and then vanishing! I wonder if spotlight can be shut down entirely and replaced.

10.4 Tiger was the last OS X where spotlight worked correctly and actually returned results from the entire indexed drive, including system files…