There was this other question asking what directories can be excluded, based on their necessity.

However, I think what I am asking is different enough to merit a separate question.

I use the Spideroak backup service, and they have some kind of system that keeps historical copies of saved files.

My intention was to simply backup my whole home directory, which is somewhere around 70GB in size.

However, it seems some directories contain cache files or other things that are updated or replaced frequently. Because Spideroak is saving every copy with every change, the space I am using on my Spideroak account is rapidly increasing and in danger of maxing out.

One solution is to white list only the directories I am sure I want to keep. However some directories are not so clear. My .mozilla directory, which contains my Firefox settings... I want to back up my bookmarks, but not things like the cache, and with all the sub-directories it's hard to know where to draw the line.

So, which directories should I definitely avoid, as they are just frequently updated cache and system files which will unnecessarily bloat my backup?

  • How is your question different from the one you linked? The answers given list the common cache directories you want to exclude.
    – djeikyb
    Aug 8, 2011 at 11:48
  • Sorry can you clarify the question further? Maybe make it a bit simpler and more canonical. I can't tell whether this is different enough to be a separate question. Aug 8, 2011 at 12:05
  • My understanding is that the other question lists directories that are unneccesary because they don't contain data worth keeping. My question is what directories are problematic from the point of view of such high activity that they bloat a back up system like Spideroak which keeps historical copies. Is that not sufficiently different?
    – Questioner
    Aug 8, 2011 at 15:01
  • 1
    @DaveMG: "Is that not sufficiently different?" It doesn't seem different to me. I think the question you linked gives the best answer: askubuntu.com/questions/40992/…
    – MountainX
    Apr 17, 2012 at 21:31
  • @MountainX Yes, the answer you linked would probably answer the question.
    – nanofarad
    May 16, 2012 at 12:15

3 Answers 3


You'll definitely want to exclude the following:

  • /proc
  • /lost+found
  • /sys
  • /mnt
  • /media
  • /dev

and everything they contain

  • 4
    but all of those are not in /home. I think he is asking about what to skip from his home directory... Also, it's probably wise to not back up /tmp while you're at it.
    – Christoph
    Aug 8, 2011 at 10:23
  • Yes, I'm only backing up directories within /home.
    – Questioner
    Aug 8, 2011 at 14:59

An extension like this that exports your bookmarks regularly solves the "what mozilla files to backup" problem.

If you use git (or any other versioning system) you might want to exclude all .git folders if the repository isn't something you need. I use git as a backup system rather than developer tool for some directories, so the repository isn't crucial if I have another backup of the most recent file(s).

  • if he excludes the .git directories, he loses his git repositories - you can hardly call this a "backup". What he wants to avoid are unnecessary or recreatable things like cache, trash, thumbnails...
    – Christoph
    Aug 8, 2011 at 12:17
  • It's a trade off. I figure git is first line defense, spideroak is second line. But that's my use of git. I agree, developers will want/need the version history retained. I'll edit my answer.
    – djeikyb
    Aug 8, 2011 at 12:21

User related cache files should be in ~/.cache directory but some software like Firefox don't use that directory like Firefox which use /home/nyamiou/.mozilla/firefox/{profile}/Cache, so you may have to check for all of your software if they do not put cache files somewhere else. Also there is files like .xsession-errors that you don't want to save because they will change very often and you don't really want to save this (it's an error log).

I'm sorry, I can't provide you a list but you probably should watch the problem the other way around and see what you really want to save instead of what you can exclude.

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