When backing up your data, you need to decide whether to back up each file and directory separately, or in an archive with a collection of other files. You also need to decide whether or not to compress your data to reduce the storage requirements for your backups.
The time lost to compression and decompression may be offset to a degree by the reduced time it takes to write or read the compressed data to media or to transfer it through a network. To reduce the expense of compression, you may choose to compress the backup copies of your data as a background task after the data has been copied—possibly days or weeks after—to reduce the storage requirements of older backups while keeping newer backups as accessible as possible.