This page tries to answer how to deal with the most popular issues.


Slow database inserts and updates

If you're:

  1. Running behind the tip
  2. Have slow canonical commit time according to the Canonical Commit Latency time chart on Grafana dashboard (more than 2-3 seconds)
  3. Seeing warnings in your logs such as
    2023-11-08T15:17:24.789731Z  WARN providers::db: Transaction insertion took too long block_number=18528075 tx_num=2150227643 hash=0xb7de1d6620efbdd3aa8547c47a0ff09a7fd3e48ba3fd2c53ce94c6683ed66e7c elapsed=6.793759034s

then most likely you're experiencing issues with the database freelist. To confirm it, check if the values on the Freelist chart on Grafana dashboard is greater than 10M.

Currently, there are two main ways to fix this issue.

Compact the database

It will take around 5-6 hours and require additional disk space located on the same or different drive equal to the freshly synced node.

  1. Clone Reth
    git clone
    cd reth
  2. Build database debug tools
    make db-tools
  3. Run compaction (this step will take 5-6 hours, depending on the I/O speed)
    ./db-tools/mdbx_copy -c $(reth db path) reth_compact.dat
  4. Stop Reth
  5. Backup original database
    mv $(reth db path)/mdbx.dat reth_old.dat
  6. Move compacted database in place of the original database
    mv reth_compact.dat $(reth db path)/mdbx.dat
  7. Start Reth
  8. Confirm that the values on the Freelist chart is near zero and the values on the Canonical Commit Latency time chart is less than 1 second.
  9. Delete original database
    rm reth_old.dat

Re-sync from scratch

It will take the same time as initial sync.

  1. Stop Reth
  2. Drop the database using reth db drop
  3. Start reth

Database write error

If you encounter an irrecoverable database-related errors, in most of the cases it's related to the RAM/NVMe/SSD you use. For example:

Error: A stage encountered an irrecoverable error.

Caused by:
   0: An internal database error occurred: Database write error code: -30796
   1: Database write error code: -30796


Error: A stage encountered an irrecoverable error.

Caused by:
   0: An internal database error occurred: Database read error code: -30797
   1: Database read error code: -30797
  1. Check your memory health: use memtest86+ or memtester. If your memory is faulty, it's better to resync the node on different hardware.
  2. Check database integrity:
    git clone
    cd reth
    make db-tools
    ./db-tools/mdbx_chk $(reth db path)/mdbx.dat | tee mdbx_chk.log
    If mdbx_chk has detected any errors, please open an issue and post the output from the mdbx_chk.log file.

Concurrent database access error (using containers/Docker)

If you encounter an error while accessing the database from multiple processes and you are using multiple containers or a mix of host and container(s), it is possible the error is related to PID namespaces. You might see one of the following error messages.

mdbx:0: panic: Assertion `osal_rdt_unlock() failed: err 1' failed.


pthread_mutex_lock.c:438: __pthread_mutex_lock_full: Assertion `e != ESRCH || !robust' failed

If you are using Docker, a possible solution is to run all database-accessing containers with --pid=host flag.

For more information, check out the Containers section in the libmdbx README.