One thing you may have noticed when using the z switch with tar is that the compression can take some time! If you look at your CPU usage, though, you’ll notice that only one core is being utilised to compress the files. In a modern system 4 or 8 cores are common, meaning that […]
Sometimes you may with to add files to an existing backup; if you issue a command like: tar -cvf /dev/st0 backupfiles …and the tape is not already set to the end of the previous archive you will over-write any data from the position on the tape. Use the “eom” command to move […]
If you have compressible data you may save space on you tapes by using compression; this comes at a cost of CPU cycles to do the compressing, which can often be a worthwhile tradeoff for a long-term backup. To do this is quite simple – add in the -z switch to your tar command. […]
Following on from the article on writing files to a tape backup, what happens if you want to back up more than what fits on a single tape? Here we want to use the –multi-volume switch, or -M. Use it so: tar -cvMf /dev/[path-to-tape] [backup folder or files] As a working example: […]
With used tape drives falling in price they are now finding their ways into the hands of more home storage enthusiasts; one should be wary about purchasing a tape drive in unknown condition, though, as there’s a good chance that it may be faulty or require servicing. One way to check the status of […]
This is just like extracting a regular tar archive: tar -xvf /dev/[path to tape] [directory or file to restore] e.g.: tar -xvf /dev/st0 backups This will restore the “backups” file/folder to the current working directory. To check your current directory, you can use: pwd to make sure that […]
To check the contents of a tape, insert the tape and run the following: tar -tf /dev/[path to tape device] e.g.: tar -tf /dev/st0 Note that typically it’s a zero, not a letter o, at the end.
To put files onto a tape, run the following: tar -cvf /dev/[path to tape] [file or directory] [file or directory] [file or directory] An example would be: tar -cvf /dev/st0 /home/bob This will back up the user bob’s home directory to the tape, here located at /dev/st0 (a typical location […]
This is another nice and easy one, though it may take a while depending on the size/speed of the tape: sudo mt -f [/path/to/tape] erase e.g.: sudo mt -f /dev/st0 erase That’s /dev/st(zero) not /dev/st(letter o), in case it’s not clear from the font. This will likely take some time […]
This again uses the mt command, and is nice and easy: sudo mt -f [path/to/tape/drive] rewind A common example would be: sudo mt -f /dev/st0 rewind Easy done! In the above example it’s st (zero) not st (letter o) – in case it’s not clear from the font.