Troubleshooting MAMP and Time Machine

Time MachineWell, it’s taken me what seems like forever, but I finally determined that MAMP has been the cause of all of my Time Machine woes. Basically Time Machine would get to a certain point, in my case it was around 29 GB, and simply stall, not allowing me to stop the backup process. I would basically have to restart the machine to get it to stop. I originally thought it was a problem with the formatting of the external drive, however I’d done all of the troubleshoot tips I’ve found on the web, to no avail. Finally let me say, I’m not a Unix expert, nor am I that well versed in file permissions. I know just enough to get myself in trouble, but I believe I understand this problem well enough at this point that I thought sharing my discoveries might help someone else avoid a similar headache.

In a nut shell, it seems that by default MAMP’s Apache instance doesn’t set a group owner for files created by the Apache server. Time Machine chokes on these files, which results in a stalled backup. After much Googling, I came across this blog post about MAMP Pro and Time Machine. I then used the Time Machine options to exclude the directory that I created for my document root (I believe MAMP defaults to /Users/foo/Sites/). Excluding my MAMP directory allowed Time Machine to completely backup my system. In the aforementioned blog post about MAMP Pro, it appears there is a preference pane in the pro version to choose your user/group for the Apache server. The free version of MAMP doesn’t offer this same preference, so I had to do a bit more digging.

What I found was that in the Apache httpd.conf file, around line 327, the group was indeed not set, rather it read “Group #-1”. From what I understand of the Apache .conf file, using the # comments out what ever follows, which is why the cache files were being created as an unknown group, or “nogroup” as the post calls them.

I solved my issue by:

  • changing “Group #-1” to “Group _www” on line 327 of the Apache httpd.conf found in Applications/MAMP/conf/apache
  • moving all the cache files that the Apache server had created in my MAMP document root to the trash
  • restarting Apache in MAMP (there’s actually no “restart”, you have to stop, then start the servers)
  • removing the MAMP directory exclusion from the Time Machine options

By all means, if there is any misinformation in this post, or you can shed further light on the subject, please leave a comment, as I would like to fully understand the issue, and as I said, the information might be helpful to others, as I haven’t found much on the subject in my searches.