Each CircleCI Xcode image has a fixed disk size and the amount of free space available can be checked by looking at the "installed software" manifests.
Depending on the types of jobs being run, it is possible to hit the following error:
No space left on device
This indicates that the disk is full and the job will not be able to continue.
Freeing Up Space
If you are not using the iOS simulators for your build, you can safely delete the following directory:
Removing the iOS simulator runtimes will free up an additional 10GB+ of disk space.
You can achieve this by adding the following step to your config.yml near the start of the job:
- run: name: Delete Simulators command: sudo rm -rf /Library/Developer/CoreSimulator/Profiles/Runtimes/