I'm trying to recover on an external hard disk two partitions that correspond to the "/" and "home" divisions of Lubuntu 19.04.
I was using my main system, Lubuntu 19.04, (which is on an external HDD) on a cousin's laptop. I noticed that for this session there were annoying freezes for no apparent reason -- I was just using Firefox --, so I opened htop (with a lot of effort) and noticed a very high consumption of RAM and SWAP.
After closing a few tabs before doing a reboot... Boom! -> I skipped the black boot screen containing the boot lines (
[ OK ] Blablablabla...). The PC is frozen at the moment. It does not react to anything.
It didn't occur to me much more than to disconnect the E-HDD, take the battery out of the laptop (it has a problem with the button), connect the E-HDD in another port to change position (it was in my bed), put the battery back in and try to start again. All in that same order.
Surprise mine that when starting the PC shows me the screen
grubrescue>_. It occurred to me quickly to relapse in the Lubuntu 18.04 of the laptop and to revise. After a brief review and confusion I discovered in GParted that the partitions /dev/sdb3 and /dev/sdb4 are shown as "unknow", but with the "Name" with "Linux filesystem" in each one.
fsck, with "-p" and "-b block_number", but the error always ends up being the same:
fsck.ext4: Group descriptors look bad... trying backup blocks... fsck.ext4: Bad magic number in super-block while trying to open /dev/sdb3 The superblock could not be read or does not describe a correct ext4 filesystem. If the device is valid and it really contains an ext4 filesystem (and not swap or ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock: [...]
It should be noted that I use GPT, not MBR. Well... So I tried all the blocks and all those tools, but nothing.
I'm researching how to use testdisk. I installed it and opened it and it recognized me a disk label that I had put before for the home page and other partitions, but I don't know exactly what "write filesystem structure" means and I'm afraid to break something.
At the moment I only have GParted running an "Attemp to Data Recover" while I investigate. At this exact moment I can't show the "minimal, reproducible example" for this very reason.
I'm pretty sure my information is still there... But I need to work with it. I don't have copies of the files I need. Every minute that passes is a little hopeless.
--- EDIT 01 ---
TestDisk doesn't work for me. It doesn't list directory files. Cannot find SuperBloks. It does not detect if it is EXT4 or what. Just take these two partitions as strange. And GParted never found anything so I closed it.
Actual GParted state Ignore "unallocated" fills.
Everything is telling me that I should do a data extraction with recovery tools. I hope the next few minutes of searching will help me not to.