For the last few weeks I’ve been receiving periodic emails from Crashplan telling me my iMac hasn’t been able to reach their servers. When I received the emails, I would check and find that the menu bar application was no longer running. I saw this two years ago when I first setup the iMac, but things had been running smoothly for a long time.

Crashplan has a great support article detailing this issue. Essentially, the Java engine can run out of memory while scanning files, resulting in a crash. You can confirm the behavior by checking the log files¹ for the string “OutOfMemoryError”.

They recommend allocating 1 GB of or memory for every 1 TB of files, with a default setting of 1 GB. My iMac has a 3 TB internal drive, and a 2 TB included in the backup, so the default 1 GB allocation is definitely insufficient. The support article details the process of changing the memory allocation, which involves entering a command in the Crashplan console:

java mx 5120, restart

I set the memory to 5 GB to match the recommendation. While I was looking into the issue, I stumbled on this post, which describes where the memory allocation value is stored. It’s in a plist file located at:

/library/launchdaemons/com.crashplan.engine.plist

There’s a string value in the plist that will have the value Xmx1024m by default. This is the memory allocation, and after changing the value through the Crashplan console, I checked the plist to confirm the change had taken.

I expect I won’t see the issue again, until the app reverts to the default setting again.