Backup Verification

Backup Verification

Test and validate backup integrity.

Quick Verification

# Check backup exists
ls -la /backup/latest*

# Check backup size (not zero)
du -sh /backup/*

# Check backup timestamp
stat /backup/latest.tar.gz

File Backup Verification

Verify Archive Integrity

# Test tar archive
tar -tzf backup.tar.gz > /dev/null && echo "OK" || echo "FAILED"

# List contents
tar -tzf backup.tar.gz | head -20

# Verify with checksum
md5sum backup.tar.gz
sha256sum backup.tar.gz

# Compare with stored checksum
sha256sum -c backup.sha256

Test Restore

# Extract to test directory
mkdir -p /tmp/restore-test
tar -xzf backup.tar.gz -C /tmp/restore-test

# Compare with original
diff -r /original/path /tmp/restore-test/path

# Cleanup
rm -rf /tmp/restore-test

Database Backup Verification

PostgreSQL

# Verify dump file
pg_restore --list backup.dump

# Test restore to temp database
createdb test_restore
pg_restore -d test_restore backup.dump

# Verify data
psql test_restore -c "SELECT count(*) FROM important_table;"

# Cleanup
dropdb test_restore

MySQL

# Verify dump syntax
head -100 backup.sql
tail -10 backup.sql  # Should end properly

# Test restore
mysql -e "CREATE DATABASE test_restore;"
mysql test_restore < backup.sql

# Verify
mysql test_restore -e "SELECT count(*) FROM important_table;"

# Cleanup
mysql -e "DROP DATABASE test_restore;"

Automated Verification Script

#!/bin/bash
BACKUP_DIR="/backup"
DATE=$(date +%Y-%m-%d)
LOG="/var/log/backup-verify.log"

echo "=== Backup Verification $DATE ===" | tee -a $LOG

# Check recent backup exists
LATEST=$(ls -t $BACKUP_DIR/*.tar.gz 2>/dev/null | head -1)
if [ -z "$LATEST" ]; then
    echo "FAIL: No backup found" | tee -a $LOG
    exit 1
fi

# Check backup age (less than 24 hours)
AGE=$(($(date +%s) - $(stat -c %Y "$LATEST")))
if [ $AGE -gt 86400 ]; then
    echo "WARN: Backup is more than 24 hours old" | tee -a $LOG
fi

# Check backup size
SIZE=$(stat -c %s "$LATEST")
if [ $SIZE -lt 1000 ]; then
    echo "FAIL: Backup too small" | tee -a $LOG
    exit 1
fi

# Test archive integrity
if tar -tzf "$LATEST" > /dev/null 2>&1; then
    echo "OK: Archive integrity verified" | tee -a $LOG
else
    echo "FAIL: Archive corrupted" | tee -a $LOG
    exit 1
fi

echo "OK: Backup verification passed" | tee -a $LOG

Cloud Backup Verification

AWS S3

# List recent backups
aws s3 ls s3://bucket/backups/ --recursive | tail -10

# Check object exists
aws s3api head-object --bucket bucket --key backups/latest.tar.gz

# Download and verify
aws s3 cp s3://bucket/backups/latest.tar.gz /tmp/
tar -tzf /tmp/latest.tar.gz > /dev/null && echo "OK"

Restic

# Check repository
restic check

# List snapshots
restic snapshots

# Verify snapshot
restic check --read-data

# Test restore
restic restore latest --target /tmp/restore-test

Verification Checklist

Verification Schedule

# Add to crontab
# Daily quick check
0 8 * * * /usr/local/bin/backup-verify.sh

# Weekly full restore test
0 2 * * 0 /usr/local/bin/backup-restore-test.sh