If you do a backup of your database (click on the radio button next to your active profile and choose “Backup” or “Backup without Logs”), the actual data is small.
If this were me, and I had to use the same physical (internal) disk, I would
- perform the “Backup without Logs” operation
- restore the ZS box to the default configuration and reboot
- format the disk as ext3
- then use the “Restore Profile” option to upload the DB I backed up to my local PC in step 1.
If you have a USB key or some other removable storage, you could first format that to ext3, copy your active profile there, then do the format of the internal hard disk and then copy the previously active profile from the USB key disk back to the internal hdd.