Better than Time Machine: backup your Mac with rsync

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We al know we need to make backups. Apparently, 30 procent of all computer users lose all of their files sometime in their life. Not a pretty foresight.

Fortunately, Mac Leopard users have a program called Time Machine that makes things a lot easier. But is Time Machine the perfect backup solution? I don’t think so. There are a couple of things that make Time Machine very unsuitable for me:

  • You need to get a seperate external hard drive that can only be used for Time Machine (and has to be formatted first)
  • That drive has to be formatted in HFS+, hence, without any (commercial) third-party plugins it’s not readable on Windows or Linux systems
  • You have to leave your drive on all the time to make sure Time Machine makes backups
  • You can’t make a list of things you want to have backed up, you can only exclude folders from your complete hard disk
  • Time Machine makes an exact copy of your hard drive

Especially that last ‘feature’ is very irritating to me. I have an external drive with about 300G of files, including lots of music and video files. My MacBook drive is only 80GB big, so i can never have the complete contents of my external drive on my MacBook. Let’s say i have 10GB of MP3 files, which i backup with Time Machine, then i remove about 5GB of files from my MacBook to free some space. What happens when the next backup round is happening? Exactly, the 5GB of files get deleted from the external disk as well. When i want to play a certain MP3 file from my external drive i now have to ‘restore’ and ‘look back in history’ to find it. Not very user-friendly.

Luckily, there is a very good (free) alternative to Time Machine that does exactly what i want with backups: it lets you specify which folders you want to backup, it doesn’t delete things on the backup drive when you delete files from your original drive, and it’s compatible with any external drive and can even backup files over a network. This piece of software is called rsync. Here’s how to use it.

rsync is a command-line utility shipped with every copy of Mac OS X. It originated from the UNIX/Linux world, where it has been part of most Linux distributions for many years. rsync is reliable, fast, and easily configurable. Try running it by opening up the Terminal.app (located in your Applications/Utilities folder) and running the command:

rsync

You’ll get an overview of all possible options. In essence the syntax is very simple:

rsync OPTIONS SOURCE DESTINATION

What you’ll probably want is a one-way transfer of all files in SOURCE to DESTINATION, where only files are copied that are not available on the DESTINATION disk or different. Aside from that you’ll want to include all subdirectories, links, permissions, date/time, groups, owner and devices. To do that simply use this easy-to-remember option list:

rsync -rlptgoD

Ha, just kidding! Fortunately there is another switch that does all of that with one switch, namely the archive switch:

rsync -a

So, let’s say you want to backup the files in your Documents directory to your external harddrive, which you appropriately named ‘backup’, then this would be the command:

rsync -a ~/Documents/ /Volumes/backup/Documents

For those of you who don’t use the Terminal very often: the tilde (~) is a shortcut for your home directory. If, for example, your name would be ‘Alice’ your home directory would probably be

/Users/alice

In essence you could write the statement above also as

rsync -a /Users/alice/Documents/ /Volumes/backup/Documents

The /Volumes/ path always leads to your drives under Mac OS X. This is also true for DMG files and CDs and DVDs you load.

An important thing to remember is that you should always include a trailing slash (/) after the SOURCE directory and no slash after the DESTINATION. If you wouldn’t do that, and you forgot the slash after ~/Documents rsync would create a directory named ‘Documents’ in the /Volumes/backup/Documents directory, so your files would eventually be backed up under

/Volumes/backup/Documents/Documents/

If you want to get a little more feedback on what rsync is actually doing you can add a few more options to let it output a little more to the screen:

rsync -a --progress ~/Documents/ /Volumes/backup/Documents

You might also want to exclude a few sub-directories or files with the backup. A good example of this is the virtual machine files Parallels makes in the /Documents/ directory and which can be quite large and will be backed up every time. If you have a large virtual machine, this could easily take 15 minutes.

rsync -a --exclude Parallels/ ~/Documents/ /Volumes/backup/Documents

Another option that you might need is when you use a FAT-32 formatted drive. FAT-32 is currently the only filesystem that is supported by all major operating systems, until Apple finally adds write support for NTFS under Mac OS X (There is a very good free / open source alternative called NTFS-3G that works beautiful, but isn’t supported officially by Apple yet). FAT-32 has a shortcoming that it can’t handle files over 4GB, which is pretty irritating if you have large DV video files or DVD backups. Another shortcoming is that it doesn’t properly set file update times, so it will copy all files, modified or not, every time you run your backup. Fortunately, there is a switch to fix this:

rsync -a --modify-window=1 ~/Documents/ /Volumes/backup/Documents

So, we have all the ingredients to make a proper backup script with only the directories you want. What i did to make my own backup script is simply copying the rsync command many times with alternate source / destination paths. A Linux guru could probably come up with a better solution, but this solution works fine for me. For some inspiration for your own backup script, here’s a portion of my script:


#!/bin/bash
rsync -a --progress --exclude Parallels/ ~/Documents/ /Volumes/backup/Documents
rsync -a --progress ~/Music/MP3/ /Volumes/backup/Media
rsync -a --progress ~/Pictures/ /Volumes/backup/Media/Pictures
rsync -a --progress ~/Backup/ /Volumes/backup/Data
rsync -a --progress ~/Movies/ /Volumes/backup/Media/Video

Note the first line of the script (‘#!/bin/bash’). This line says that it is a script executed by the shell. To make this script runnable you need to set some permissions. If you named your script ‘backup’ this would be the command

chmod u+x backup

Now simply run the backup script at any time you like and be very happy knowing that your data is safe on your external hard drive!

Just one last word of advice: rsync isn’t as fool-proof as Time Machine. If you would, let’s say, per accident swap the SOURCE and DESTINATION values you would lose data. Be very careful before running your backup script with any valuable data.

So, hopefully this article has given you some advice on how to use rsync to back up your Mac. Feel free to drop any comments in the comment field below.

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28 comments

  • Better than Time Machine: backup your Mac with rsync

    […] Game Posts wrote an interesting post today onHere’s a quick excerpt We al know we need to make backups. Apparently, 30 procent of all computer users lose all of their files sometime in their life. Not a pretty foresight. Fortunately, Mac Leopard users have a program called Time Machine that makes things a lot easier. But is Time Machine the perfect backup solution? I don’t think so. There are a couple of things that make Time Machine very unsuitable for me: You need to get a seperate external hard drive that can only be used for Time Machine (and has to be […]

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  • jon

    “You need to get a seperate external hard drive that can only be used for Time Machine (and has to be formatted first)”

    False.

    The hard drive can be used for other things as well. It doesn’t have to be external either. It doesn’t even have be separate, but you’d be stupid to think that backing up your only hard drive to your hard is any kind of protection.

    Still, it doesn’t seem time machine is a good match for you since you don’t want the kind of backup solution it offers (complete and mindless backups).

  • Tim

    This was just what I was looking for. I have an old HHD from old PC. And just want to backup the Documents folder on my new iMac. And do it whenever I what, whithout having the HDD on all the time. Much, much easier than figuring out how TimeMachine works/doesn’t work. thanks!

  • Grover

    Thanks for the very straightforward overview of using Rsync. It was exactly what I needed to solve a problem I was having.

    @jon
    Is Time Machine your girlfriend or something? Why are you taking it personally that Mr. Kranen wants to use something else?

  • Xl Organism

    This was exactly what I was looking for. Thanks for posting this. Ciao!

  • Kranki

    1) TimeMachine does not do a complete backup of your harddrive. Do a full restore and you will find (for instance) that you are missed the “/User/Shared/SC Info” directory which is your iTunes authorization data. Apache will be missing a directory.
    2) I have yet to do a full TimeMachine backup and have it be 100% of what I used to have. For instance, recently my harddrive failed and I did have to do a full restore. Well, things like Terminal started having lines through it that just did not exist prior to the backup.
    3) If it were implemented as a full backup such as what you can do with asr or hdiutil, but with history. Then I would be more positive on it. But for now it is back to rsync, hdiutil and asr.

  • Anonymous

    What would be your strategy for creating multiple backups…as in how Time Machine keeps archives of backups along the lines of daily/weekly for up to one month? I like Time Machine, but I don’t like that it requires my network drive to be on all the time. I’d rather make one backup per day (not hourly like Time Machine wants), but also be able to keep archives as far back as one month, like this:

    1. Daily backups for one week (last 7 days worth)
    2. Weekly backups for one month (4 backups)

    Hopefully I’m explaining this clearly. Thanks.

  • Hay

    @09: you could write a cron job that makes a backup every day and another one that archives them weekly. Note that this means that you end up with many duplicates of the same files, that might fill up your backup disk pretty quickly. The beauty of Time Machine is that it takes up less space because it uses symbolic links.

  • dantux

    If anyone is interested, I posted some time ago, my rsync backup script. It does just that: saves hourly, daily, weekly, monthly, yearly backups using the same concept as Time machine does (hard linking). This does not hard link directories, but does for existing files, which saves a lot of space.
    Check it out:
    http://dantux.com/weblog/2009/03/23/using-rsync-as-a-backup-solution/

  • Drew Stephens

    Time Machine actually uses hard links, not symbolic links, allowing the oldest backups to be removed when space runs out on the backup drive.

  • WeaselSpleen

    Yo, Time Machine is MY girlfriend, you best step back son.
    Nobody treats her betta than me.

  • Mr MArk

    Hey Guys,

    Just thought you should know the RSYNC that shops with osx does NOT backup OSX File Metadata efficiently!

    This sucks. Read this for more info..

    http://www.bombich.com/mactips/rsync.html

  • Dov

    FAT32 can handle drive up to 16 TB, the 4GB limit is imposed in Microsofts Format command which artificially limits the ability to create large volumes.

    This seems originally to be a move to force people to upgrade from Win98 to win2000 and NTFS if they want large disk support. Most external hardrives are formatted as FAT32 using the manufacturers own version of a formatting tool with no 4GB limits at all

    There are utilities that will format a FAT32 volume in excess of 4GB that can be found with a simple web search

  • Anonymous

    As a new Apple user – this is another example of an OS not allowing it’s users any flexibility.

    Backup via Time Machine could be useful if it was written in such a way as to allow the user to choose what is backed up and schedule it accordingly.

    I know, Apple people will bleat loudly, but the OS has some significant drawbacks for users that know what the are doing and, don’t want be nannied.

  • Anonymous

    TimeMachineEditor lets you adjust the interval that TimeMachine backs up at. http://timesoftware.free.fr/timemachineeditor/

  • Anonymous

    You need to get a seperate external hard drive that can only be used for Time Machine
    -> Wrong! You can backup to a partition on your internal harddisk if you want. (Would be stupid, but it IS possible) Also, the same goes for EVERY other backup program. Also, the disk is NOT exclusive for Time Machine. It’s just a drive with files and you can add/edit/delete files all you want.

    (and has to be formatted first)
    -> Depends; I ALWAYS buy Western Digital drives in the Studio range; preformatted for mac. My choice. If you choose another; formatting takes about 3 minutes.

    That drive has to be formatted in HFS+, hence, without any (commercial) third-party plugins it’s not readable on Windows or Linux systems
    -> We’re backing up a Mac, what’s wrong with using a Mac file system? Second; the better linux distros can read HFS+ without any trouble. It’s Windows that sucks big time.

    You have to leave your drive on all the time to make sure Time Machine makes backups
    -> Well, I’d like you to show me ANY ONE backup that can backup to a disk that is not on.

    You can’t make a list of things you want to have backed up, you can only exclude folders from your complete hard disk
    -> Which serves it’s purpose very well; that way you cant forget to include newly created files/folders.

    Time Machine makes an exact copy of your hard drive
    -> As opposed to ….. what, exactly? What is wrong with having a full copy of your drive? I don’t want to spend hours reinstalling my OS, then my Apps and then my files after a crash. I used to have to do that with WIndows and I’m sick and tired of that. With Time Machine, i place a new drive, boot from the OS CD and recover my drive. Easy as that.

    I really like your approach with rSync, but your reasoning is flawed.

    @Anonymous #16; As a new Apple user – this is another example of an OS not allowing it’s users any flexibility.
    -> OSX _IS_ giving it’s users all the flexibility it can give; Use Time Machine for a full backup with revisioning, or use rSync (shipped with it) for the more complex tasks. Compared to windows; no backup software to speak of, no revisioning, no rsync.
    On a Mac, there is NO reason whatsoever to not backing up your harddisk. On Windows there is, well, windows IS the biggest reason but that’s beyond the scope of this topic.

    @Kranki #8
    I do not share your (bad) experience with Time Machine. I’ve restored not many machines but a few and all of them restored without any problem whatsoever (including our mac mini server that lost a drive due to a power outage)

  • Anonymous

    Why do so many say it’s silly to backup a hard disk to another portion of the same hard disk? For me, one HUGE value of backing up (with whatever method, but preferably with some form of history) is to get an earlier version of a file I messed up. In fact, that’s the only reason I’ve ever actually used a backup in practice (I admit: I’ve been lucky). OK, it WOULD be silly to not ALSO backup to an external drive for protection against the drive crash scenario… It does happen, I know. And I will do that too. Just don’t discount the value of a simple historical copy of the work you do as part of everyday workflow.

    For the curious: I use TM to backup up my SSD drive to the internal HD on my iMac. In addition, I use a sym link from my desktop to a “working” directory on the HD (I don’t want my every day files to start filling up the SSD), and hoped that TM would back up that working directory too. Not surprising, but unfortunate: it faithfully backed up the sym link, but that’s it — meaning that the TM backup process doesn’t FOLLOW the sym link and backup the files & directories it finds there. (Of course, I can’t use a hard link since it’s across file systems.) So an rsync solution such as described here is something I’m considering for that “working” directory.

    Similarly, I’ll probably develop an rsync solution to fully backup the HD to an external device, for that rare day when the HD decides to croak. Yes, I could use TM itself, manually switching it from the SSD to work instead with the HD, then switching back after its done (yuck) — or fool with the TM plist to do the switching. Much to do, much to learn….

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  • James

    Can both Source AND Destination be external, or does one have to be in home directory/interbal? I’ve got an external drive of >1TB and I’d like to sync its backup to it.

    Thanks,

    James

  • lucidsystems

    If you are using rsync for backups on OS X, then you may also find LBackup of interest : http://www.lbackup.org

    LBackup is an rsync wrapper designed for backup of user data.

  • Brian H

    Yes, James, I’m synching two external drives as we speak. Many folks put pictures and movies on external drives to save space on their computers, but fail to back those up.

  • joe

    rsync -a is missing -H

    So, if you want to preserve hardlinks then you need to add that option.
    This will increase the amount of time it takes for the overall rsync to perform.

    And, this is not necessary if you are backing up directories that you know do not include hardlinks. However, if you are backing up system directories, you may want to be sure and include that option.

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  • Terry Flannery

    Many thanks for the excellent doc.

  • flow in

    thanks hon, works well. to share to a windows box, i mounted the windows share onto the mac (adding the share mount into the login items) then rsync’d to the mac’s mounted volume – rsync wouldn’t work direct to the shared folder.