Can Time Machine use two HDD's?

Discussion in 'Mac Accessories' started by halfmonkey, Mar 21, 2014.

  1. halfmonkey macrumors regular

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    May 17, 2011
    #1
    I was wondering if Time Machine can use two different hd to back up data? What I mean by this is can I use one hd with Time Machine to say back up my iMac and then a second hd with Time Machine to back up my external drive that holds my pictures? I'm asking because instead of buying one super large capacity ext hd to back up all drives onto one hd, I'm thinking I would like to just use some of my extra hd laying around. Plus, the larger capacity ext hd seem to only come in RAID configuration and I prefer to not have it configured as RAID.
     
  2. mentaluproar macrumors 68000

    mentaluproar

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    #2
    Time machine can use two hard drive to back up your mac. It's automatic and simple. Just hit select disk in the time machine preferences pane and tell it to add disk when it asks.
     
  3. Alrescha macrumors 68020

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    Jan 1, 2008
    #3
    No, Time Machine will not back up your two drives to separate disks. Time Machine will back up multiple disks, and it will use multiple backup destinations, but those destinations will contain everything.

    You can have Time Machine backup your internal disk, and create your own method to back up the external. Carbon Copy Cloner, SuperDuper, or rsync in Terminal can be used to manually or automatically back up your secondary disk.

    A.
     
  4. ColdCase, Mar 21, 2014
    Last edited: Mar 21, 2014

    ColdCase macrumors 68030

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    #4
    In other words, you can only define one backup set in time machine. You can send the backup of that set to several different disks, but they will all be the same.

    Programs like CCC allow you to define several different backup sets and they can be scheduled independently.
     
  5. RMo macrumors 65816

    RMo

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    #5
    Alrescha is correct about your situation. (Mentaluproar is correct too in general but apparently didn't catch the details about what you wanted.)

    I suggest using TimeMachine with your internal hard drive if that is where you primarily work with your data. For the external drive, how often do the contents change? If it's not too often, you might be OK doing it manually from time to time or using a utility like the Unix rsync tool, which comes with OS X. You can Google around for a few Mac guides on that if it doesn't sound too scary. Of course, commerical utilities can also help you here (and there may be free ones as well--anyone?).
     
  6. halfmonkey, Mar 21, 2014
    Last edited: Mar 21, 2014

    halfmonkey thread starter macrumors regular

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    #6
    So it sounds like I'm not gonna be able to do what I want to do. Just to make sure folks are responding with the best answers because I realize I didn't provide all details when originally asking the question, I'll break it down now.

    I have an iMac with an internal 1tb hd. I have an ext 3tb hd where I store all of my imported AVCHD videos from my camcorder to work with iMovie. I have another ext 2tb hd that hold the archive of said videos from my camcorder. This is in case my 3tb ext hd ever fails, I can always reimport from the archive hd. I planning on purchasing another ext hd, maybe about 3tb to hold all of my pictures. So with this configuration, I'd have a total of 9tb to back up.

    I could go and purchase a 10tb ext hd to back this all up but I'm wondering if I can break it up with a new ext hd of 5tb to back up the movie drives (the 3tb iMovie and the 2tb archive hd) and then another ext hd of 4tb to back up the 3tb picture ext hd and the 1tb internal iMac hd?

    So if I go with this format, I'd need Time Machine to recognize or at least allow me to say back up drive 1 should only back up the iMovie and Archive ext hd and back up drive 2 should only back up the 3tb picture hd and the 1tb internal hd. Can this be done?

    If I go the 10tb ext hd, I'm only finding RAID configured ext hd with thunderbolt whereas if I break it up, I can find regular hd with one being maxed out at 5tb and the other configurable to 4tb. These would not be RAID configured and just regular hard drives.

    Thoughts, suggestions, comments?
     
  7. ColdCase macrumors 68030

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    #7
    I use CCC to back up my external drives to a second drive the same size daily or so. I have one backup drive for each primary drive. I use TimeMachine to backup my main drive. CCC used to be free but is not bad a price currently and worth it. Its more cost effective that way than buying a 10TB volume, which you can only do in a RAID. 4TB USB drives are currently less than $150, 3TB less than $100.

    I avoid cable clutter around the iMac by hanging my backup drives off a TimeCapsule (the backup is wireless). I use 4TB drives, the first backup takes several hours, but much shorter subsequently as only the files that change are transferred.
     
  8. Chancha macrumors 6502

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    Mar 19, 2014
    #8
    Time Machine while generally reliable for the average user, it actually gets decreasingly effective as you approach multiple number of disks of multiple TBs. The requirement of having to use a single logical volume for whatever data setup is reason enough to move away from it, at least partially for your backup strategy.

    I would say keep Time Machine only for the boot drive, where TM deals with system files best and in the event you need a TM restore or migration to other Macs of newer OS X, this helps a lot (but you should keep a bootable clone also as TM does not do this). For other less frequently accessed media, especially large ones like movie files, I see no real benefit of relying on TM to back these up as they hardly ever change, and are often subject to be moved on other volumes as your projects move on. TM is just not friendly with this kind of setup where many semi-professionals or high enthusiasts often find themselves walking into.

    Like the others suggested, use a cloning app that supports incremental backups and also scheduling if possible, this way there is close to nothing you lose going from TM. Some say TM is great at finding a lost file or a file that you accidentally delete, but in that case you should use a proper versioning archiving workflow, not rely on software like TM where it actually deletes the oldest copy when it needs space, without even asking.
     
  9. RMo macrumors 65816

    RMo

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    #9
    I just discovered this: http://lifehacker.com/5543791/back-up-your-mac-to-multiple-disks-with-time-machine

    It's a few years old (and, more importantly, a few OS versions old) now, so I don't know if it still applies, but it looks like it might be a way to get your disks to do what you want using plain Time Machine.

    I don't think you're likely to find a single 3.5" disk at this time larger than 4 TB, so you will have to use some sort of multi-disk configuration if you want Time Machine to back up to a single, large volume. You don't need a RAID enclosure; JBOD can also be configured to present drives (of various sizes) to the OS as one large volume. Of course, you lose redundancy like you can get with some RAID configurations, but that may not be an issue for home backups.

    I'm starting to think such an enclosure might be your best bet if you don't mind the initial investment in the enclosure itself.
     
  10. Alrescha, Mar 21, 2014
    Last edited: Mar 21, 2014

    Alrescha macrumors 68020

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    #10
    I agree with most things in your post except this. 1) Time Machine deletes the oldest 'backup', not the oldest 'copy'. If you keep the original file, Time Machine keeps a copy of that forever. Time Machine will eventually delete files that you have deleted. 2) Time Machine notifies you if when the old backups are deleted - you can turn this off if you want in System Preferences.

    A.
     
  11. Chancha, Mar 21, 2014
    Last edited: Mar 21, 2014

    Chancha macrumors 6502

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    #11
    Thanks for bringing this up, I was trying to shorten the post so I didn't elaborate on those points.

    You are right, my choice of word was off, obviously the context of what I mentioned meant otherwise, as I said Time Machine does not deal well with human deleted files. From my experience, what happens in TM when it needs space is this: compare the backups against your current state -> determines how many files are no longer on the current source, which means safe to delete -> deleting all instances in the TM drive that contain these files, so freeing up space. This has 2 problems: 1) it means TM only keeps deleted files to a certain point, determined by the capacity of your backup drive and also how much data has changed over the course of the backup history, and 2) it also means if your move around large media files across volumes a lot, which I mentioned in my previous post is what video pros do all the time, TM will need to re-backup as it does not recognize files appearing on a new volume as the same as the old one, despite the fact they are. In a real clone app such as CCC, the first problem can be solved as easy as a check box that says "move to a temporary archive folder" which you can decide their fate later.

    As for notification of deleting old backups, I don't know if 10.9 has changed as I only have experience up to 10.8 and mostly 10.6, is that the Sys Pref option you mentioned actually only notifies you *after* it is done deleting. This caught me off guard a few times in the past.
     
  12. ColdCase macrumors 68030

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    #12
    I guess I don't see your point as that can be said for all but the most robust backup $oftware.... but I may be missing something.

    Most backup programs delete oldest archived files when disk space gets low, if they archive files at all. You can set it to not delete archives, but they get angry when the disk fills and starts sending nasty messages. You used to be able to set TimeMachine to do the same, but I'm not sure about the recent version.

    There are more robust server based backup software apps that will automatically move to another drive when the first one fills.

    Pros move files from working storage to archive storage, sometimes but rarely move them back. Most pros I know use CCC to backup their archive drives (usually a couple copies) and time machine their working drive to a local USB disk if the working drive is small, otherwise they use a local JBOD or RAID. It may seem like some work for TimeMachine, but thats what its designed to do and works well seamlessly in the background. For versioning, they typically use the built in capability of their editing apps.


    There is not much difference in $$$ between JBOD and RAID boxes.. especially for the OPs iMac application. eSATA is not an option without converters.
     
  13. islade macrumors newbie

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    Mar 6, 2014
    #13
    Is time machine not a good option to back up 4-6tb of data?
     
  14. FreakinEurekan macrumors 68040

    FreakinEurekan

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    #14
    It's not, in that it's difficult to find a media (single volume) that can hold 4-6TB of data plus reasonable versioning. For 6TB of data in Time Machine, I'd want a destination of 12TB ideally, or 9TB minimum. So that means an array, and if you want some modicum of protection from failed media then a RAID 0/1 (six 4TB disks) or a controlled RAID5 (four 4TB disks plus a controller) just for your backup destination.

    Even if you assume lower overhead for versioning (e.g. a lot of the data is static, like a media library) you're still exceeding the capacity of a single spindle destination, which makes redundancy more expensive and complex.

    A hybrid solution - using TM for your day-to-day data with the media library (or whatever your major usage is) excluded, then a custom solution with CCC or some other tool for that large data set, will work better.
     
  15. ColdCase, Mar 23, 2014
    Last edited: Mar 23, 2014

    ColdCase macrumors 68030

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    #15
    Its a good option if you don't mind a bit of extra cost for a large enough volume (disk space). As mentioned, if you care about recovering deleted files, you should supply 8-10TB of storage space for Time Machine. It is simple just to pick up a 10-12TB box and use timemachine to backup. Its also simpler to recover data.

    Currently it seems to be less money to break up the source files into junks that fit on 4TB USB drives, however. You would use time machine for your OS and files and something like CCC for the other media. It is much more complicated to set up, however. Whether that is a good option or not for you may be more subjective.

    A 8TB box is about $500-600, two 4TB drives are about $350 on sale $440 otherwise.... 12TB box is about $700-850, three 4TB drives are about $425 on sale, $660 otherwise. There are other factors, like failure modes and recovery efort... but those are typically less significant than the cost difference. The bit more money may be worth the simplicity to you. You may be able to find an 8 - 10- 12 TB box on sale.
     

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