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Research Links

• GAI: bitcoin-core IO error how to fix
• StackEx: When should I use -reindex-chainstate and when -reindex
• windows bitcoin core where is blockchain stored?  — C:\Users\YourUserName\AppData\Roaming\Bitcoin

 

Note:  What is "reindexing"

-reindex:

• wipes the chainstate (the UTXO set)
• wipes the block index (the database with information about which block is where on disk)
• rebuilds the block index (by going over all blk*.dat files, and finding things in it that look like blocks)
• rebuilds the chainstate (redoing all validation for blocks) based on the blocks now in the index

-reindex-chainstate:

• wipes the chainstate
• rebuilds the chainstate using the blocks in the index you had before

The latter should be strictly faster, as it does not need to rebuild the block index first. Perhaps the progress bar during reindex confuses you: that progress is only for the rebuilding of the index. The recreation of the chainstate happens after that rebuild is completed.

You should use -reindex only when you were running in pruning mode, or if you suspect the blocks on disk are actually corrupted. Otherwise, when you only suspect corruption of the chainstate (which is far more likely), use -reindex-chainstate.

 

 

 

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GAI: bitcoin-core IO error how to fix

An IO error in Bitcoin Core typically indicates corrupted block files. To fix this, you can either redownload the entire blockchain by deleting corrupted files or attempt to repair by reindexing the blockchain. If that fails, consider copying data from a known good node. 

Detailed Solutions:

1. 1. Redownload Corrupted Files:

   • Stop Bitcoin Core and locate the data directory (default locations are described on Bitcoin.it). 
   • Delete all .dat files (e.g., blk0009.dat) and *.rev files starting with the block file that the error reports, and any subsequent block files. 
   • Restart Bitcoin Core. It will redownload the missing blocks and subsequent blocks. 
   • Consider using -reindex=1 to ensure data consistency after the redownload. 

2. 2. Repair by Reindexing:

   • Stop Bitcoin Core.
   • Run Bitcoin Core with the -reindex option (e.g., bitcoin-qt -reindex=1). 
   • This will rebuild the chainstate data structures, which may fix the corruption. 

3. 3. Copy from a Known Good Node:

   • Find a Bitcoin Core node that you know is working correctly.
   • Copy the blocks directory (excluding the wallet directory) from the good node to your data directory. 
   • This will replace your potentially corrupted block files with known good ones. 

4. 4. Hardware Issues:

   • If the issue persists after software fixes, check for potential hardware problems, such as a weak power supply, by running debug commands and checking the powerWARN value. 
   • Consider formatting your hard drive fresh or replacing it if you suspect hardware corruption. 

Important Considerations:

• Data Consistency:

  Always use the -reindex option after any major changes to the blockchain data to ensure data consistency. 

• Redownloading is a Long Process:

  Redownloading the entire blockchain can take a significant amount of time, potentially up to a few days, depending on your internet connection.