As part of the upgrade process to Daedalus 0.12.0 (Released on December 18, 2018) a process has been implemented in Daedalus wallet to optimize block storage. This optimization process runs in the background and will stop when files in the local copy of the blockchain (on your machine in the DB 1.0 folder) are missing or corrupted. This will block Deadalus wallet from working.
- Sync stalled: If you are syncing, syncing will get stuck/stop progressing.
- Connecting to Network...: If you are already synced and using Daedalus you will get a Connecting to Network error.
- Recovery Stalled: If you are recovering your wallet, the recovery process will get stuck/stop progressing.
Optimized block storage will significantly reduce the number of files and space needed to store the Cardano blockchain data on your machine. Instead of using one file per block (one file for every 20 seconds of blockchain history), the blockchain is now stored in two files per epoch (two files for every 5 days of blockchain history). Only the most recent epoch of the blockchain will continue to be stored as one file per block, this is to facilitate easier handling of blockchain rollbacks. This will reduce the number of files needed to store the blockchain from about 1.5 million to less than 50,000 files for one year of blockchain history, which will significantly improve performance.
The optimization process was added in 0.12.0 and runs in a separate thread. It does not communicate with Daedalus so when it stops it stops Daedalus too.
Optimization of blockchain data will take some time for users who have upgraded Daedalus 0.12.0. The reduction in the number of files and the amount of disk space used will NOT happen immediately after upgrading. The optimization process takes some time, users should keep Daedalus 0.12.0 running for between 2 hours and 24 hours for the optimization of data to complete. Depending on their personal computer performance. For users with SSD drives optimization should be much quicker.
So if you see the blockchain taking a long time to sync directly after upgrading please be patient and give it some time to complete.
If you have problems described above with Daedalus wallet especially within 24 hours of upgrading to version 0.12.0 it may be because of optimization running in the background and has stopped due to missing or corrupt files in your local copy of the blockchain. Rebooting your machine is the first thing to try to resolve your issue. If that does not help please Delete and restore blockchain data
Deleting and restoring blockchain data will still download the 1.5 million files but optimization will be happening at the same time. It would be advisable to do this overnight when you are not using your machine. Please see the article Delete and restore blockchain data for important details on that.
It is important to note that optimization is only likely to cause issues just after upgrading to Daedalus 0.12.0 although it is an ongoing process that keeps optimizing block files into epoch files because of the large amount of optimization that has to take place to get the blockchain converted to epoch files.
We are currently working on a solution to this problem.
See also Optimization Status Indicator feature request.