Help me, Dr. Internet!
I can't really get a straight answer on this, and am hoping someone out there has a good solution.
Every year, I make a huge several-terrabyte backup of my entire system. When I was on Windows, I used RAR for this. Good compression, was able to break it up in 4GB file blocks to make file access easy if I needed something off the backup or repair an archive.
I've long since moved to TAR.XZ for intermediate backups, but the access takes forever cause it's a single archive, so I've never used it for my large once-a-year-complete-backup.
That said, the question: would it be worth doing the Full Everything Backup with tar.xg over jumping into Windows to WinRAR it (Day 9023849283468923 of my 30 day trial!)? In general does RAR pack tighter than TAR.XZ? Can TAR.XZ break itself into chunks for easier access?
My update is scheduled for January 1st. Any help would be appreciated! And thanks in advance!
@dolari It's a little bit old and doesn't have .xz in the results but
https://ubuntuguru.wordpress.com/2007/03/09/whats-the-best-file-compression-method/
indicates you might get a little bit better compression if you use 7zip? You'd have some similar tradeoffs to rar in that it supports random access to the archived data but does not store UNIX permissions.
@dolari (oh, *and* 7zip is well supported on both linux and windows. you wouldn't have to switch OSes to use it.)
@MorningSong - For a while I used 7Zip, but I stopped about a decade ago when an archive broke and there were zero recovery options for it. I looked into it again after someone told me that 7Zip was better compression, and thier recovery irons were a bit...arcane.
@dolari Fair!
I don't know how RAR recovery is, but it *is* worth noting that this author has another strike against .xz along those lines, specifircally citing its error recovery being unreliable.
@MorningSong - I've found a good set of strings for RAR archiving that worked for me. I actually installed WinRAR on a Windows partition, clicked all the buttons and clicks I use for my yearly updates, and found the corresponding strings. I think I managed it!
Incremental Monthly Home Directory Backup
rar a -m5 -r -s -v5370000 -x/home/dolari/.local/share/Trash/ -ep2 -ol -rr -taYYYYMMDDHHSS -tbYYYYMMDDHHSS "YYMM Incremental Nayru Home Directory Backup.rar" /home/dolari/
Incremental Monthly Backup:
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DUMP/Videos/" -x"/mnt/The Archive/.Trash-1000/" -x"/mnt/The Archive/Working Directory/" -ep2 -ol -rr -taYYYYMMDDHHSS -tbYYYYMMDDHHSS "YYMM Incremental Backup.rar" "/mnt/The Archive"
Full Home Directory Backup
rar a -m5 -r -s -v5370000 -x/home/dolari/.local/share/Trash/ -ep2 -ol -rr "YYMM Nayru Home Directory Backup.rar" /home/dolari/
Full Yearly Backup
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DU
@dolari nice!
I should probably automate my backups at some point.
@MorningSong - THANK YOU for that link though. Shows that RAR is the better compression! I guess I just need to figure out what my miles long command line it's gonna be. :)
@dolari If you want to retain random access of files in the archive, avoid tar. tar produces an uncompressed archive of everything passed into it, and it's format is very sequential. If given a compression argument, then as a convenience, it'll compress the archive once it's built. Hence the dot-tar-dot-xz extension; if you un-xz that file, you'll get a single file (the tar file) as a result.
I seem to recall that there's an implementation of RAR for Linux/BSD platforms; can you use that to retain your desired accessibility?
@vertigo - there is a RAR implementation for Linux but it's all command line and I was trying to avoid a mile long typing adventure for all the options I use in WinRAR (File Roller will use RAR once it's installed but won't give you a lot of the advanced features I need). Plus if TAR.XZ gives better compression I'd take "waiting to find the file" hit.
@vertigo - Looks like I got it!
Home Directory Backup
rar a -m5 -r -s -v5370000 -x/home/dolari/.local/share/Trash. -x/home/dolari/.var/app/com.valvesoftware.Steam/ -ep2 -ol -rr "YYMM Nayru Home Directory Backup.rar" /home/dolari/
Incremental backups:
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DUMP/Videos/" -x"/mnt/The Archive/.Trash-1000/" -x"/mnt/The Archive/Working Directory/" -ep2 -ol -rr -taYYYYMMDDHHSS "YYMM Incremental Backup.rar" "/mnt/The Archive"
Full Yearly Backup
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DUMP/Videos/" -x"/mnt/The Archive/.Trash-1000/" -x"/mnt/The Archive/Working Directory/" -ep2 -ol -rr "YYYMM Full Backup.rar" "/mnt/The Archive"
Looks like I got it!
Home Directory Backup
rar a -m5 -r -s -v5370000 -x/home/dolari/.local/share/Trash. -x/home/dolari/.var/app/com.valvesoftware.Steam/ -ep2 -ol -rr "YYMM Nayru Home Directory Backup.rar" /home/dolari/
Incremental backups:
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DUMP/Videos/" -x"/mnt/The Archive/.Trash-1000/" -x"/mnt/The Archive/Working Directory/" -ep2 -ol -rr -taYYYYMMDDHHSS "YYMM Incremental Backup.rar" "/mnt/The Archive"
Full Yearly Backup
rar a -m5 -r -s -v5370000 -x"/mnt/The Archive/Videos/" -x"/mnt/The Archive/00_DUMP/Videos/" -x"/mnt/The Archive/.Trash-1000/" -x"/mnt/The Archive/Working Directory/" -ep2 -ol -rr "YYYMM Full Backup.rar" "/mnt/The Archive"