The crazy thing I did to fix Yosemite performance

Jeremy Huddleston Sequoia jeremyhu at
Mon Nov 3 11:24:51 PST 2014

> On Nov 2, 2014, at 10:06, Jeff Singleton <gvibe06 at> wrote:
> Hi,
> So after much frustration, much stress, and of course, I broke my Mac in the process. Backed up my user folder from single-user mode (since my mac would not boot all the way). Then I wiped and reinstalled Mavericks, upgraded to Yosemite, and then restored my user folder.
> Back story: In an attempt to figure out why the services mds and mdworker were running away with my CPU. Nothing I did resolved this, including putting every single folder except /Applications in the exception list for Spotlight.

mds and mdworker are Spotlight.  They run at low priority and will chew up CPU and disk I/O to index your system.  You should expect them to be a bit more active than normal after an OS upgrade.

If you see abnormal behavior, you can run mddiagnose to create a zip file containing logs and other useful information for debugging.  Submit a bug report at and include the diagnostics.

> This is where I started editing LaunchDaemons and LaunchAgents and where breakage occurred.
> So...
> This literally resolved all of the performance issues I saw reported from many others besides myself about the performance of Yosemite via the standard upgrade path.

Can you elaborate on "This"?  What do you mean?  What solved your performance issues, and what perf issues were you having?

> On Nov 2, 2014, at 16:54, Jeff Singleton <gvibe06 at> wrote:
> Trust me.  I tried everything. Resetting the SMC, PRAM, permissions

Which should have nothing to do with the issue.

> , manually deleting the .Spotlight folder from /. Anything I could find on any Apple related blog/forum, I tried it.

Deleting .Spotlight would just keep Spotlight chugging along as it will want to replace the now-missing data.

> Even going so far as to exclude lots of folders from my home Library folder, the same for System Library folder, my external drive, Bootcamp partition...none of it mattered.

Did you take a look at logs to see what it was indexing.  A quick check of fs_usage should tell you what files are being indexed currently.

> The only thing that had any affect was to stop the mdworker services and the syslogd service.

mdworker, yeah.  If you stop it, it won't run.

syslog has nothing to do with it.  It's just logging what it's told to log.  If you see a lot of CPU usage from syslogd, check what is actually being logged as certainly something else is just being very noisy, and that's what you want to look at rather than syslogd.

> That is the only time the CPU usage dropped and the fans started slowing. Of course, right after I rebooted, they started back up again.
> Somewhere in the middle of all that I probably forgot to revert an edit on one of the plist files and thats when it stopped booting to the GUI. Single-user mode was the only way, which required manually mounting my external drives and copying my user folder to it.
> Booted to my Mavericks USB installer, completely wiped the main drive, installed Mavericks, and upgraded to Yosemite. Then booted to single-user again, and restored my user home folder.

Seems a tad... excessive...

> From that point, mdworker did its initial indexing, and then dropped down to normal usage. Now the fans only spin up when I am actually doing something like compiling something under MacPorts.

And do you have anything which can be used to try and determine what was actually going on with your system at the time?  Did you take a sysdiagnose or mddiagnose?


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