Month: November 2017

Using rar for backups

Some suggestions for using rar (or Winrar, if you translate the command line switches to the GUI equivalents) to backup folders. This are the “must” options:

-ma5 RAR5.0 Format
-m5 Compression (0: store, 1: min … 3: default … 5: max), I would use -m5
-htb BLAKE2 checksum (CRC32 is much to unreliable)
-qo+ “Quick open”, some additional data to open large rar archives quicker
-ts “Time stamp” in highest precission and all types
-rr1 “Recovery Record” 1% additional data to recover from up to 1% corruption in rar archives
-hppwd Encrypt headers and data with pwd

The following options are sensible but you have to check your use case. If you either make one time backups you would go add and lock: “rar a -k …”, or you make incremental backups, then it is update and keep versions: “rar u -ver3 …”

-r Recurse into subdirectories
-ep1 Remove base paths
-ow -ol -oh Save file security data, handle links
-k Lock archive (not with u)
-u (a -u = u) Update archive (not with -k)
-ver3 Versions of changed files to keep 3 (not with -k)
-v5g  Split archive in 5 gigabyte large chunks (not with u and therefore -ver)