Backup

rsync is the standard for efficient file transfer. It only copies what changed, handles interruptions gracefully, and works over SSH. Here’s how to use it well. Basic Syntax 1 rsync [options] source destination The trailing slash matters: 1 2 rsync -av src/ dest/ # Contents of src into dest rsync -av src dest/ # Directory src into dest (creates dest/src/) Essential Options 1 2 3 4 5 6 -a, --archive # Archive mode (preserves permissions, timestamps, etc.) -v, --verbose # Show what's being transferred -z, --compress # Compress during transfer -P # Progress + partial (resume interrupted transfers) --delete # Remove files from dest that aren't in source -n, --dry-run # Show what would happen Common Patterns Local Backup 1 2 3 4 5 # Mirror directory rsync -av --delete /home/user/documents/ /backup/documents/ # Dry run first rsync -avn --delete /home/user/documents/ /backup/documents/ Remote Sync Over SSH 1 2 3 4 5 6 7 8 # Push to remote rsync -avz -e ssh /local/dir/ user@server:/remote/dir/ # Pull from remote rsync -avz -e ssh user@server:/remote/dir/ /local/dir/ # Custom SSH port rsync -avz -e "ssh -p 2222" /local/ user@server:/remote/ With Progress 1 2 3 4 5 # Single file progress rsync -avP largefile.zip server:/dest/ # Overall progress (rsync 3.1+) rsync -av --info=progress2 /source/ /dest/ Exclusions 1 2 3 4 5 6 7 8 # Exclude patterns rsync -av --exclude='*.log' --exclude='tmp/' /source/ /dest/ # Exclude from file rsync -av --exclude-from='exclude.txt' /source/ /dest/ # Include only certain files rsync -av --include='*.py' --exclude='*' /source/ /dest/ Example exclude file: ...

tar (tape archive) bundles files and directories into a single file. Combined with compression, it’s the standard way to package and distribute files on Unix systems. The Basics 1 2 3 4 5 6 7 8 # Create archive tar -cvf archive.tar /path/to/files # Extract archive tar -xvf archive.tar # List contents tar -tvf archive.tar Understanding the Flags 1 2 3 4 5 c = Create archive x = Extract archive t = List contents v = Verbose (show files) f = File (next arg is filename) So tar -cvf = Create, Verbose, File. ...

rsync synchronizes files between locations — local to local, local to remote, remote to local. It’s smart: it only transfers what’s changed, making it fast for incremental backups and deployments. Basic Syntax 1 rsync [options] source destination Local Sync 1 2 3 4 5 6 7 8 9 # Copy directory rsync -av /source/dir/ /dest/dir/ # Copy directory (trailing slash matters!) rsync -av /source/dir /dest/ # Creates /dest/dir/ rsync -av /source/dir/ /dest/ # Contents into /dest/ # Dry run (show what would happen) rsync -avn /source/ /dest/ Remote Sync (SSH) 1 2 3 4 5 6 7 8 9 10 11 # Local to remote rsync -av /local/dir/ user@remote:/remote/dir/ # Remote to local rsync -av user@remote:/remote/dir/ /local/dir/ # Different SSH port rsync -av -e 'ssh -p 2222' /local/ user@remote:/remote/ # With SSH key rsync -av -e 'ssh -i ~/.ssh/mykey' /local/ user@remote:/remote/ Common Options 1 2 3 4 5 6 7 8 9 -a, --archive Archive mode (preserves permissions, timestamps, etc.) -v, --verbose Verbose output -n, --dry-run Show what would be transferred -z, --compress Compress during transfer -P Progress + partial (resume interrupted transfers) --progress Show progress --delete Delete files in dest not in source -r, --recursive Recurse into directories -h, --human-readable Human-readable sizes Archive Mode (-a) -a is equivalent to -rlptgoD: ...

Everyone has backups. Few have tested restores. The backup that fails during a crisis is worse than no backup — it gave you false confidence. Backup strategy isn’t about the backup. It’s about the restore. The 3-2-1 Rule A minimum viable backup strategy: 3 copies of your data 2 different storage media/types 1 copy offsite P C C C r o o o i p p p m y y y a r 1 2 3 y : : : : P L R O r o e f o c m f d a o s u l t i c e t t s e i n r o a e a n p p r s l c d h i h a o c i t t a v a e b ( ( a s d ( s a i d e m f i e f f e f d r e a e r t n e a t n c t e r n e p t g r e i o r o v ) n i ) d e r ) What to Back Up Always: ...

A practical guide to backups and disaster recovery — automated backup strategies, testing your restores, and building systems that survive the worst.