Prevent HDD spin-down / keep disk always active

[inlinecoder]

Hi,

First of all, great work on this project — getting SMB running on Time Capsule hardware is impressive.

I’m considering repurposing a Time Capsule as a lightweight always-on SMB device with a larger NAS-grade HDD (8–12TB), and I have a question regarding disk power management.

Is it possible (or already supported) to prevent the internal HDD from spinning down?

My goal is:

• Keep the disk always spinning (no sleep / no standby)
• Avoid latency when accessing files over SMB
• Use a NAS-grade drive designed for 24/7 operation

From what I understand, spin-down behavior could be controlled by:

• macOS / underlying system power management
• disk firmware (APM / AAM settings)
• or low-level utilities (e.g., hdparm-like controls, if available)

Questions:

1. Does this firmware expose any control over disk sleep/spin-down?
2. Is there a way to disable it via config, launchd, or system tweaks?
3. If not, would this be feasible to implement?
4. Are there hardware or thermal constraints that would make this unsafe?

I’m fine with higher power usage and wear — the priority is consistent availability and responsiveness.

Thanks.

[hbokh]

2. Is there a way to disable it via config, launchd, or system tweaks?

One option is to modify drive settings via SSH after a reboot, using the atactl command.

atactl wd0 setidle 0
atactl wd0 setstandby 0

atactl wd0 checkpower
Current power status: Active mode

The default idle time is set to 300:
https://github.com/jamesyc/TimeCapsuleSMB/blob/main/src/timecapsulesmb/deploy/planner.py#L36

This setting was added recently (May 14th) in commit 61c66c.

[jamesyc]

After a deploy:

1. SSH onto the device
2. Edit /mnt/Flash/tcapsulesmb.conf
3. Change ATA_IDLE_SECONDS to 0

This change will survive reboots, but not redeploys.

[hbokh]

There's no editor "in the device". 😇
Run this instead:

sed 's/ATA_IDLE_SECONDS=300/ATA_IDLE_SECONDS=0/' tcapsulesmb.conf > tcapsulesmb.conf.tmp && mv tcapsulesmb.conf.tmp tcapsulesmb.conf

[hbokh]

@jamesyc Since this is the "idea section": could we get an option to set / override the internal drive idle time, specifically ATA_IDLE_SECONDS=300 from the .env file, please?

The drive in the Time Capsule "tower" is the <APPLE HDD ST3000DM001, AQ52> and I'd like to have some additional control over the drive and its setting to keep it alive for a bit longer than most of them.
See why here:

• https://en.wikipedia.org/wiki/ST3000DM001#Cause

When the Time Capsule is now turned on again or wakes up from hibernation, the data disks of the Seagate hard drive are destroyed because the deformed read-write unit drags onto it.
Source: https://9to5mac.com/2021/07/08/apple-time-capsule-failure-hard-drive/

[jamesyc]

Yeah sure. Create an issue at https://github.com/jamesyc/TimeCapsuleSMB/issues and tag it "enhancement"

[jamesyc]

I don't get notifications for Discussions, so it's way easier to get my attention via creating an issue