Well…tried everything I could think of and finally had to figure something was majorly corrupt on the SD card so I took a new card, reinstalled and all is OK now. Interestingly, the apparently failed SD card was only in service for 6 months
It is now possible to run a RPI from a USB SSD drive and those are way easier to maintain in a good shape for a lot longuer time. I know those draw a lot more amp than an uSD card and they cost more, but we can have some nice 120Gig SSD for cheap Look at this.
10 years ago, I did it on a intel atom board. I just copied a usb sd stick to ssd using a clone program.
The original was a normal acid install on a sata mounted sd card. A mounted volume is a mounted volume and cloneable
But linux has command line options for copying whole drive contents with boot record using ’ dd ’ but your devices need to be unmounted.
I can’t begin to remember the options but I’m sure you can find them.
I will say I had so many less problems with sd cards when I started using korean made cards like samsung. You get what you pay for sometimes. But ssd is the way to go especially if you do a lot of experimenting. But quality here can be a issue as well. Whole disk imaging on occasion works well for backup of any media.