today my node somehow failed, it was suddenly out of sync and can’t be synced since then. The status display shows 0/1.436.170 which makes me think that the node can’t find a block on the system anymore. Also nothing is synchronized, that stands now already for over one hour in such a way. I have already performed several reboots.
How do I get this to work again?
Thx CD
What chia software version? The logs say you ran out of memory - this was a known issue in versions earlier than 1.2.6
I’m running the current release 1.2.11…
Thx CD
Something seems to have broken. I have now started a replica from this morning of the Ubuntu server on another VMWare host and now the node syncs again. I have to catch up 4000 blocks now but it should be done by tomorrow.
When this is actually running, I would like to turn it around again or copy the blockchain to a new host. Is that possible? Could I possibly even use a different platform? For example, migrate from Linux to macOS? I currently have a few retired Minis, which would also have a bit more power like the virtual Linux here.
Thx CD
Yes, you can copy blockchain database files to another computer, so that it doesn’t need to sync that much.
Just make sure to stop all chia processes before copying it, to avoid corrupting the database.
chia stop all -d
Run this and watch process list until you make sure there are no more chia processes/daemons running (sometimes I had to run this command multiple times and wait a few minutes)
Unexplainedly, the replica of the node got the same problem during the night. I found some forum threads with one or the other error message in my debug.log and it looks like the database is corrupt.
I am now sticking to my plan B and installing a new node on a retired Mac Mini and of course it makes no sense now to take the database from the old node. But I would have liked to take over all the keys from the old system, how do I proceed now? On the new node the keys directory in the chia/mainnet directory does not exist yet.
Thx CD
You can initialize new node with mnemonic passphrase. This will generate new ssl keys and certificate authority, but the farmer private key will be the same (so you can harvest existing plots).
Not sure if I’d try to reuse the db files if they are corrupted. It would take days to sync from scratch probably 
The speed of syncing depends on the speed of your computer, so if that Mac Mini has some slow CPU, it will take some time.
An alternative is to use https://www.chia-database.com/
You can download it to your original box, and check whether it will start working right away.
Servus Jacek,
the tip with the database as download was great. But I was also lucky that the database was just 19 minutes old when I downloaded it. After about an hour the database was fully synced in the new node.
What then took a few hours was the synchronization of the wallet and at this point I had to wait until the wallet had found all the relevant blocks, which was the case at about 700,000 blocks, but then the wallet was also connected to the pool and all payouts were entered correctly.
What was also a bit of a challenge was configuring the harvester to the new node, since it runs in a Docker container on a Synology NAS. Here I had to transfer the new certificates of the wallet (or the node?) to the harvester and initialize them there (chia init -d path/to/the/newca/directory).
All in all an exciting process, good to have done it once and nice to be back on track.
Thanks for your support
CD