如何每日导出Redis数据库并在午夜清空其全部数据？

Got it, let's tackle your two requirements: nightly Redis data exports and midnight database flushes. Since your business only runs 8:00–20:00 and all daily tasks wrap up after that, we can safely schedule these operations during off-hours without disrupting anything.

1. Nightly Redis Data Export #

You’ve got two solid options here, depending on whether you need a binary backup (for fast restoration) or a human-readable export.

Option 1: Use Redis' Built-in RDB Snapshot #

If your Redis instance is already configured to generate RDB snapshots (check your redis.conf for save directives), you can leverage that for backups. To trigger a manual snapshot for your nightly schedule:

• Run the background save command to avoid blocking Redis (though since your business is offline, even the blocking SAVE is safe):

  redis-cli BGSAVE
  

• Once the save finishes (confirm with redis-cli LASTSAVE to get the timestamp of the last successful save), copy the dump.rdb file to your backup location. Add a date stamp to keep backups organized:

  cp /var/lib/redis/dump.rdb /path/to/your/backups/redis_backup_$(date +%Y%m%d).rdb
  

Adjust the paths to match your actual Redis installation—common RDB locations are /var/lib/redis/ or /etc/redis/.

Option 2: Export to a Human-Readable Format #

If you need to inspect the exported data easily, use redis-cli to dump keys and values to a text file:

# For a structured text dump (good for small to medium datasets)
redis-cli KEYS "*" | while read key; do
  echo "Key: $key | Value: $(redis-cli GET "$key")"
done > /path/to/your/backups/redis_text_backup_$(date +%Y%m%d).txt

Note: For very large datasets, KEYS * can be slow—swap it out for the SCAN command if needed, but since Redis is quiet overnight, KEYS should work just fine.

2. Clear Redis Data at Midnight #

To start fresh every day, use Redis' FLUSHALL command—it deletes all keys from all databases in your Redis instance.

Safe Execution #

Since your business isn’t running after 20:00, running this at midnight carries zero risk. Execute it with:

redis-cli FLUSHALL

If your Redis requires password authentication, add the -a flag or authenticate first:

# With password flag
redis-cli -a your_redis_password FLUSHALL

# Or authenticate within the CLI
redis-cli AUTH your_redis_password FLUSHALL

3. Automate Everything with Cron #

To make these tasks run automatically every day, set up cron jobs on your Redis server.

1. Open your crontab editor:

   crontab -e
   

2. Add these lines to schedule the export (e.g., at 21:00, right after business hours) and flush at midnight:

   # Export Redis data daily at 21:00
   0 21 * * * redis-cli BGSAVE && cp /var/lib/redis/dump.rdb /path/to/your/backups/redis_backup_$(date +\%Y\%m\%d).rdb
   
   # Flush all Redis data daily at midnight
   0 0 * * * redis-cli FLUSHALL
   

The \% escapes are necessary in cron because % has special meaning (it denotes newline characters). Adjust the paths and times to fit your needs.

Quick Checks Before Going Live #

• Permissions: Make sure the user running the cron job has read access to dump.rdb and write access to your backup directory.
• Test Manually: Run the export and flush commands once first to confirm they work as expected.
• AOF Persistence Note: If you use AOF instead of RDB, run redis-cli BGREWRITEAOF before copying the AOF file to ensure it’s consistent (or stick with BGSAVE to generate an RDB snapshot for backups).

内容的提问来源于stack exchange，提问作者jdog