need help recovering my database from bitcoin core 27.1.0

So here’s the deal: I just upgraded from Ubuntu 20.04 to 22.04, but the drive with my node's database is on a hard drive. I need to manually mount it in fstab and change the permissions for the whole disk. I messed up when I ran the new version of Bitcoin Core, and the settings.json file got wiped clean. Now, even though I have my data, Bitcoin Core wants me to start downloading everything from 2009 again!!! Someone online suggested just copying the backup, but that hasn’t worked. Every time I open Bitcoin Core, it deletes all the data. The data is safe in the chainstate.back and blocks.back directories. Can anyone help me figure out how to create a settings.json file that would also include my secured wallets? I really need assistance here.

It's just in simple json format. For wallet, simply type your wallet file names exactly like this (except the exact wallet's name); For one wallet: For two or more wallets: The gist is, if there's two or more wallets, put a "," sign after the wallet name, if it's the last/single wallet, do not include a ",". The "wallet name" are the folders you can find inside "wallets" directory, add the quotation marks as shown in the examples. That'll work assuming that every setting is set correctly and chainstate & blocks folders are intact. I assume that when you try to load the wallet files which are auto-unloaded by the blank "settings.json" file, your pruned node asked for --reindex which triggers the IBD. Also, you might have set some incompatible settings in the GUI before, that you haven't set in the new install, specially: "Prune block storage" settings. If so, you can re-initialize Bitcoin Core with: $ bitcoin-qt --choosedatadir set your previous settings and point it to your data directory. Alternatively, set your previous settings to your bitcoin.conf file.

Well i had to restart a new blockchain, but curiously when 2024arrive, the ratio of downloading fail under 0.02% per hour if i do nothing, moreover i was frequently shut down of the core. So this is a tip : select your peers, it's very very important, you must disconnect who lock your downloading process and maybe nukers. https://www.haku.fr/nodes.png

I'm pretty sure this is just due to your Hard Drive being the bottleneck and that estimate is always way inaccurate if the datadir is in a slow hard drive and with low dbcache. Of course, getting bad peers can be an issue too but seeing those "ping" values, most of them should be sufficient and fast enough to download the blockchain. It's just your node is struggling with all the processes including the script verifications that's skipped in the older blocks, as well as your settings (if you're using the default) and the slow hard drive. Since you've started IBD (Initial Block Download) instead, let's just assume that this thread's issue is now solved.

I've never had to manually block peers. It normally works fine on it's own. Agreed. In 2024, Ordinal spam caused chainstate to grow fast. If you don't have enough RAM and use an SSD, this is going to be very slow. I (still) have my blocks directory on HDD, but chainstate has been on SSD for years. That makes a huge difference in download speed, while it doesn't take too much space on your SSD. If you don't have an SSD: buy one