I was having issues with OctoPrint not being seen from Cura, so I decided that perhaps something I recently did with plugins where I disabled/enabled some had broken something and that I should revert to a previous backup. I made a new backup and reverted to the previous one. It restored successfully but it made no difference, Cura was still not seeing it.
To my surprise however I then found that not only had the new backup I made just before now been lost by the restore, but so had all the other backups.
Did I miss a warning about this when I did the restore? If not, then perhaps there should be one or better still maybe don't delete backups - I couldn't see an option, but maybe the ability to specify a location outside of OctoPrint for the backups would make this simpler so that a restore needs not worry about them.
In the end I made a new backup, downloaded it then completely wiped the SD card of my Raspberry Pi and restored the backup to the new install. It again restored just fine but didn't fix my Cura issue - it still cannot find OctoPrint, and neither can any of my Windows PCs, but entering the server details manually fixed the issue.
The way the backup restore works is taking the zipped up config & data folder and extracting it over the old one. That includes the backups.
What could be done is renaming the old folder, unzipping and then restoring backups. I don't want to create a separate storage location for the backups, that will only cause issues and also litter the target system.
Could you please create a feature request so this doesn't get lost?
After taking a backup via OctoPrint, I use the download button and transfer the file to my desktop. There are numerous reasons for needing to do a restore, and a large portion of them have "something wrong with the SD card" as part of the reason. I think it makes sense to not have your backups stored on that SD card (in any folder).
In my opinion it should either always stay on the SD card or never stay on it.
I just used the restore function (twice in a row) to restore some settings deleted by a plugin bug. I just discovered that all all backups disappear after restoring. Luckily I had downloaded the last one, but was about to not do it...
My opinion differs from yours. When a backup is taken, writing it (initially) on the same media (the SD card) that it is backing up is the simplest way to guarantee the backup destination exists. However, this is, IMO, the worst destination for the long term storage of backups because the primary failure requiring the use of a backup is a corrupted SD card. After I take a backup, I immediately download it so its on a different media.
I'll grant you that there are some failures, like your plugin bug, that it might be more convenient if the backup remained after a restore, but if you are covering the corrupted SD card case, then it's not that much more work to upload before the restore.