Backup

Nightly rsync and the heat problem

When I first set up a nightly cron job to copy my home directory to an external SSD, the laptop’s fan stayed at full blast all night. The CPU hit 90 °C, and the battery life dropped noticeably. I blamed the SSD’s sluggish write speed, but the real culprit turned out to be the I/O scheduler giving the backup process too much priority. Adding ionice -c3 (the idle class) to the rsync command brought the temperature back to sane levels without sacrificing backup reliability.

The tar command is a cornerstone utility for Linux users, providing powerful features for archiving and managing files. Short for “tape archive,” tar has its roots in creating backups on magnetic tape drives but has evolved into a versatile tool for packaging files and directories into single archive files, often with integrated compression.

What is tar?

The tar utility creates and extracts archives—collections of files stored together in a single file. These archives are not inherently compressed, but tar is commonly paired with compression tools like gzip, bzip2, or xz to produce compact, compressed archives.