Accidental Technologist

Musings about Entrepreneurship, Technology and Software Development

  • Home
  • About
  • Still River Software
  • Privacy Policy

Powered by Genesis

Speeding up Slow Time Machine Backups on macOS

November 6, 2018 by Rob Bazinet Leave a Comment

Tweet

I’ve been a long-Time Apple Time Machine for many years and it’s saved me many times.

I back up to a Synology NAS drive configured with Time Machine support. Time Machine has always been fast and efficient until I upgraded to macOS El Capitan (10.11). During that time, backups could be measure in hours instead of minutes previously. I initially thought the slowdown had to do with a recent software change in my Synology NAS.

I spent a bit of time in the Synology forums trying to solve the problem with various suggestions from users. Nothing worked.

I upgrade to macOS Sierra (10.12) and High Sierra (10.13) when they came out, hoping something had changed that fixed the agonizingly slow backups. No luck.

Disabling Throttling

I recently started to try to find a solution again since my backups recently went up in size and the slowness was really noticeable. Estimated backup times measured in days. After a bit of digging I found this suggestion, entered in a Terminal window:

sudo sysctl debug.lowpri_throttle_enabled=0

It worked beautifully. A very large backup went from days to hours. Subsequent backups now take minutes instead of hours.

Note: you can re-enable throttling with a similar command:

sudo sysctl debug.lowpri_throttle_enabled=1

I admit I don’t know the side effects of disabling throttling, so use at your own risk.

Making it Stick

If you want to have throttling turned off between Mac restarts, you have to do a bit more work.

Create a file under /Library/LaunchDaemons/fix-el-capitan-slow-time-machine-speed.plist with the contents:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>fix-el-capitan-slow-time-machine-speed</string>
    <key>ProgramArguments</key>
    <array>
      <string>/usr/sbin/sysctl</string>
      <string>debug.lowpri_throttle_enabled=0</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
  </dict>
</plist>

Make it belong to root:

sudo chown root /Library/LaunchDaemons/fix-el-capitan-slow-time-machine-speed.plist

Make it load at startup:

sudo launchctl load /Library/LaunchDaemons/fix-el-capitan-slow-time-machine-speed.plist

Conclusion

I’ve also tested on macOS Mojave (10.14.1) and can confirm a nice speedup. Overall, everything works really well now. I can’t take credit for the solution as I did some searching and came across several places this was mentioned, including one from Apple. I just know that it works!

Share this:

  • LinkedIn
  • Twitter
  • Facebook
  • Email
  • More
  • Pinterest
  • Tumblr
  • Pocket
  • Reddit

Filed Under: Mac Tagged With: macOS, Synology, Time Machine

Recent Posts

  • How to Fix Rails Flash Rendering When Using Hotwire
  • Hotwire Fix for CORS Error when using Omniauth
  • Fix Installation of Ruby using rbenv on macOS Big Sur
  • RailsConf 2021 and the Future of Conferences
  • Fixing Out of Diskspace Errors on Amazon EC2

Categories

Services I Love

HatchBox - Easy Rails Deploys Fathom Analytics
Follow @rbazinet

Rob Bazinet
@rbazinet

  • This is so true! I'd love to call out some companies attempting this and making life hard on devs. https://t.co/oNayiZdKlc
    about 1 month ago
  • I’m looking for a good Mac client app to backup my Mac to my Synology NAS. Any suggestions? I’m looking for something besides Arq 7.
    about 3 months ago
  • Hotwire Course Early Access is Open https://t.co/GeW2W0HLYI
    about 4 months ago
  • The James Webb Space Telescope is an amazing engineering fest playing out in real-time - https://t.co/FlGn7LXgkY
    about 5 months ago
  • This is pretty slick - https://t.co/iYYbfNELII. Works with Edge on the Mac, but some limitations on Firefox.
    about 6 months ago
  • RSS - Posts
  • RSS - Comments
loading Cancel
Post was not sent - check your email addresses!
Email check failed, please try again
Sorry, your blog cannot share posts by email.