Why do my drives keep going to sleep and how do I prevent it?

If your drives are spinning down or going to sleep unexpectedly, this is almost always a macOS energy saving feature, not a SoftRAID issue. macOS aggressively manages drive sleep to conserve power, and this behavior can change between macOS versions.

Why this is a problem:

When drives in a RAID volume go to sleep, they need to spin back up before SoftRAID can access them. This can cause:

• Delays when accessing files
• Volume access errors
• Unexpected unmounting

Does SoftRAID have any control over drive sleep?

No – drive sleep is managed entirely by macOS. SoftRAID has no ability to override macOS energy saving settings. If none of the above solutions resolve the issue, the problem may be specific to your macOS version – check Apple’s support pages for known energy saving issues.

Solutions

Option 1: macOS System Settings

macOS Sequoia (15.x) / macOS Tahoe (26.x):

• Go to System Settings → Energy
• Uncheck ”Put hard disks to sleep when possible”
• Go to System Settings → Lock Screen
• Set display sleep to ”Never” (when plugged in)
• Go to System Settings → Displays → Advanced
• Check ”Prevent automatic sleeping on power adapter when display is off”

For laptops (additional step):

• Go to System Settings → Battery → Options
• Uncheck ”Put hard disks to sleep when possible”

Option 2: Using the Terminal.app (pmset command)

For more control over sleep settings, you can use the pmset command in Terminal. This is particularly useful if System Settings options aren’t working as expected.

To disable drive sleep:

sudo pmset -a disksleep 0

To check your current power management settings:

pmset -g

To restore default settings:

sudo pmset -a disksleep 10

Note: The -a flag applies the setting to all power sources (AC and battery). Use -c for AC power only, or -b for battery only.

Option 3: Third-Party Apps

Several free or low-cost apps can prevent your drives from sleeping by periodically “touching” (accessing) the drives to keep them active:

Amphetamine (free – Mac App Store):

• Highly configurable keep-awake utility
• Can be set to keep drives awake based on schedules, conditions, or indefinitely
• Allows you to keep drives awake while specific apps are running

Caffeine (free – Mac App Store):

• Simple one-click solution to keep drives active
• Less configurable than Amphetamine but very easy to use

Note: These apps work by periodically accessing your drives to prevent them from spinning down. They are a good solution when System Settings changes don’t persist after a restart, or when you need a quick temporary fix.