I see that due to problems with data corruption for APFS sparse bundles, the new version of Docker for Mac is reverting to the QCOW2 format after you do a “reset”.
How do I force it keep using APFS and not QCOW2. I am well aware of the data corruption issue, but for my particular use case the QCOW2 implementation is totally unusable for me. I would rather continue working with the APFS raw format even knowing the risk of data corruption.
How can I pass a flag or whatnot to force a reset to continue to use APFS instead of QCOW2?
Since in 25 days I received nothing but crickets to my original post, I was forced to spend a few hours hunting the solution myself.
For anybody else having this problem, the solution is simply to edit ~/Library/group.com.docker/settings.json and make sure to rename the diskPath value to it ends with .raw instead of .qcow2.
Hopefully Apple fixes their APFS bug in the meantime just make sure you have plenty of free disk space and you’ll be fine.
Thanks for updating your post @brianjsw, it helped me find what I was looking for.
After upgrading the Docker version, now 18.06.1-ce-mac73 (26764), I was having some networking trouble, and while troubleshooting I reset settings, etc. Unintentionally lost the custom location I was using fore the qcow2 file and the images I was currently working with. Using the UI I was not able to select the qcow2 file, it was expecting to write a new raw file, but modify the settings.json, which I found here: /Users/bstauner/Library/Group Containers/group.com.docker/settings.json, I was able to reuse my qcow2 file. Once I’m ready to convert I know where I can go to change it back.
P.S. Hopefully this helps someone else out with the updated location of the appropriate settings.json file.