Explain Redis persistence mechanisms.

Beginner

Answer

Redis offers two persistence options:

RDB (Redis Database Backup):

  • Point-in-time snapshots
  • Compact binary format
  • Good for backups and disaster recovery
  • Can lose data between snapshots

AOF (Append Only File):

  • Logs every write operation
  • Better durability (can be configured for every operation)
  • Larger file size
  • Slower restart times
# RDB configuration
SAVE 900 1      # Save if at least 1 key changed in 900 seconds
SAVE 300 10     # Save if at least 10 keys changed in 300 seconds

# AOF configuration
appendonly yes
appendfsync everysec  # Options: always, everysec, no