Making a backup - ish-app/ish GitHub Wiki
Make a backup!
If you have any worthwhile data in your file system, you really should do a backup before any major operation on the file system!
Do this by going into Settings - Filesystems - Select the one labeled as "Mounted at /" - Export. Once it is compressed you can select a location and name for this export.
If something goes wrong, all you need to do is to go to Settings - Filesystems - import and select your exported FS