Backing up external drives that aren't always connected?

I've got external hard drives for each of my clients. I'll connect them to my machine for a few days, then remove them and it might be months before they're connected again.
Will TM backup these externals (assuming I don't exclude them) and then keep that backup even if they're not connected for a long time? Or will it delete that backup after a period of time if the drive hasn't been reconnected?
Thanks!

TM only keeps hourly backups for 24 hours and daily backups for 30 days. Beyond that, TM keeps a weekly snapshot for as far back as you have disk space available. So depending on when you have the external drive connected, you could get no backup if connected less than 1 hour; a backup for no more than 24 hours if the external is not connected for the first backup of the day (between midnight and 1 AM); or a backup for no more than 30 days if the external is not connected for the first backup (between midnight and 1 AM) of the seventh day. Put another way, to guarantee a weekly backup, an external drive would have to be connected for a full seven (24 hour) days.
There may be further complications. TM needs to recognize a reconnected external drive as the same unit that was previously backed up or it is going to rebackup the entire external drive. This will very rapidly eat up your available TM backup disk space. I had two same model external drives that are only occasionally connected. I found that, for reasons I could not figure out, one of these was recognized by TM as having been previously backed up; the other was not.
Since I use these externals to store video files that change very infrequently, I gave up using TM to back them up and repartitioned my backup disk to have separate partitions for each external with the remainder for TM. I back up the externals with SuperDuper! as necessary and let TM backup just my internal drive. I don't think this will work for you since it seems you are dealing with many different client drives.

Similar Messages

  • Backing up an external HD that's not always connected?

    I just bought a Time Capsule to backup my MacBook and an external HD. I've set up Time Machine to backup the MacBook and external HD. But the external HD isn't always connected to my MacBook. When Time Machine runs its hourly backups, if at that moment the external HD is not connected, it backs up just the contents of my MacBook.
    I've just started this process, rather than learn by trial and error I'm hoping some of you have already done something similar and can share your experience. I have a couple of concerns:
    1) If Time Machine backs up my MacBook (MB) and external hard drive (EHD) and then, on a second run, with the EHD disconnected, backs up only the MB, the next time a backup runs while the EHD is connected, will it have to start all over again copying all of the contents of the EHD? Or can it recognize the EHD content which is unchanged from the last time it did a backup with the EHD connected?
    2) When Time Machine runs out of space and starts deleting old backups, is there a risk that this way I could lose a backup copy of the EHD? For example suppose Time Machine backs up my MB and EHD. Then say for a couple of weeks I don't connect the EHD and meanwhile TM keeps doing backups and runs out of space. When it throws out the oldest backups, if none of the more recent ones contain data from my EHD, do I thereby lose that backup data?
    Apologies in advance if this question has already been answered elsewhere. I've tried searching for answers but all my searches on "time machine external hard drive" just turn up results about using TM to back up to an external HD or else talk about what format a drive needs to be in order to get backed up via TM.
    p.s. I use the EHD to store, among other things, my iTunes library. So in practice I rarely go more than a day of using the MacBook without turning on the EHD. Still, I'd like to understand how TM manages backing up of drives that aren't always available.
    Thanks,
    Ben Ellis

    ben_ellis wrote:
    I just bought a Time Capsule to backup my MacBook and an external HD. I've set up Time Machine to backup the MacBook and external HD. But the external HD isn't always connected to my MacBook. When Time Machine runs its hourly backups, if at that moment the external HD is not connected, it backs up just the contents of my MacBook.
    I've just started this process, rather than learn by trial and error I'm hoping some of you have already done something similar and can share your experience. I have a couple of concerns:
    1) If Time Machine backs up my MacBook (MB) and external hard drive (EHD) and then, on a second run, with the EHD disconnected, backs up only the MB, the next time a backup runs while the EHD is connected, will it have to start all over again copying all of the contents of the EHD? Or can it recognize the EHD content which is unchanged from the last time it did a backup with the EHD connected?
    it's supposed to be smart and recognize the old backups and not redo the entire backup of the EHD in such situation. but sometimes TM does not do that for whatever reasons (=bugs). hopefully it won't affect you.
    2) When Time Machine runs out of space and starts deleting old backups, is there a risk that this way I could lose a backup copy of the EHD? For example suppose Time Machine backs up my MB and EHD. Then say for a couple of weeks I don't connect the EHD and meanwhile TM keeps doing backups and runs out of space. When it throws out the oldest backups, if none of the more recent ones contain data from my EHD, do I thereby lose that backup data?
    yes, in that scenario you will loose all backups of the EHD. that's why you need to make sure that your TM drive is big enough and has plenty of space to store incremental backups so that this is unlikely to happen. and back up the external regularly.
    Apologies in advance if this question has already been answered elsewhere. I've tried searching for answers but all my searches on "time machine external hard drive" just turn up results about using TM to back up to an external HD or else talk about what format a drive needs to be in order to get backed up via TM.
    p.s. I use the EHD to store, among other things, my iTunes library. So in practice I rarely go more than a day of using the MacBook without turning on the EHD.
    Still, I'd like to understand how TM manages backing up of drives that aren't always available.
    Thanks,
    Ben Ellis

  • I have a Seagate Freeagent 1TB external drive that ejects it's self in the middle of the time machine backup, then disappears and can't be found unless I turn it off and back on again

    I have a Seagate Freeagent 1TB external drive that ejects it's self in the middle of the time machine backup, then disappears and can't be found unless I turn it off and back on again. Any ideas?

    Hmmm.. sorry to jump in but...
    I Wish I had seen this before I got mine.
    Mine has been doing this auto eject stuff too.
    I think I just plugged it in and TM let me select it but is it possible
    I should have reformatted it with DU first, like with all the WD drive problems ?
    Is it too late for that ?
    Or just try to return it or get rid of it ?
    TIA

  • I'm a new MAC user and I'm trying to transfer my iTunes music files to my Mac, however when I attach the external drive that contains the music files, they aren't visible on the MAC (but they are visible on my old PC).  How do I get my music loaded?

    I'm a new MAC user and I'm trying to transfer my iTunes music files to my Mac, however when I attach the external drive that contains the music files, the music files aren't visible on the MAC (but they are visible on my old PC).  How do I get my music transferred?  I have already exported the purchased music from the iTunes library, but I have thousands of songs from my private CD collection that I had previously loaded through iTunes.

    Paragon Software has the most reliable NTFS driver for Mac
    tips on importing and organizing, transferring from Windows etc
    http://www.apple.com/support/itunes
    http://www.ilounge.com

  • How to transfer iTunes Music stored in an External Drive that I use for my Windows PC and use it in iTunes on Mac?

    Hi just bought my first Mac (a 2013 13' MacBook Air). Before I owned this computer I used (and still use) a Windows Desktop. My Windows Desktop (which runs Windows 8.1) has a 1TB Hard Drive that was getting pretty full so I moved all of my iTunes Music, Movies, and TV Shows onto a 2TB external hard drive. This meant that iTunes would open/work even if the external hdd was not plugged in, but only when the external HDD is plugged in do I see all of my downloaded/ripped music/movies/tv shows. Now that I own a Mac I would like to do the same thing - have all of my media on an external drive that is plugged in via USB. So my question is (A) how do I make my itunes media stored on this external HDD accesible to the iTunes on my MacBook, (B) do I need to partition the external HDD to do this, and (C) because I fully intend to keep using the drive with my Windows PC (it stores a complete backup as well as a ton of Steam videogames), will I need to totally erase the drive in order to create such a partition?

    Before we can help you, you must tell us how you are backing up your data.
    Allan

  • How to limit the external drives that Bridge searches?

    I'm experiencing the problem that I find myself working on the files chosen from Bridge that have been selected from my external drive.
    This can lead to catastrophic results, of course, when the user will overwrite the wrong files, etc.
    I have looked all through the Bridge preferences, but I can't find anyplace to limit the searches to just the original main hard drive.
    Of course it's nice to have backup on the external drive, (which I have cloned with Carbon Copy Cloner)... but often I look up from working on a photoshop file and realize I've been working on a file that originated from the external drive, and not the original HDD.
    This is driving me nuts! 
    So.... is there any way to limit the external drives that Bridge will search?
    Thanks!
    jn

    So.... is there any way to limit the external drives that Bridge will search?
    Yes, in the find menu (cmd+F or menu:Edit/Find) you have a window that let's you select the source where to look in, if you choose your hard drive as source to look in it will only find the files there.
    The folder panel may also be useful for your purpose, although I personally almost never have need for the find option in Bridge it might be when having Bridge pointed to a certain disk or folder the quick find field top right in Bridge window might also do the trick for you.
    Of course it's nice to have backup on the external drive, (which I have cloned with Carbon Copy Cloner)...
    I would not use Carbon Copy Cloner for back up but a dedicated back up application like Synchronize Pro, Just copy the whole content you want to use for back up to an external HDD and customize Synchronize the way you like it (when to back up, archive the older files etc etc). There are also a lot of other (some free) back up utilities.

  • How to transfer iTunes library to an external drive (thats easy!) but keeping the playlists musics on the computer?

    How to transfer iTunes library to an external drive (thats easy!) but keeping the playlists musics on the computer?
    Many thanks!

    Select a single song with a broken link, press CTRL+I to Get Info, cancel when asked to locate the track and take a look at the Summary tab. Post back where iTunes is looking for the file. It begins file://localhost
    Where is it really?
    Please post back both paths so that I can make suggestions. Full paths please, exact spellings, you can replace your user name with <User> if needed.
    tt2

  • HT201250 Can time machine back up external drives to external drives?

    I was wondering if I can use Time Machine to back up external drives. I know it backs up just my Mac, but need to know if
    it will back up an external drive to an external drive.

    Open your Time Machine drive. Open the Backups.backupdb folder therein. Open the Computer Name (e.g., Adam Smith's iMac) folder. Open any folder there whose name contains a date later than when you attached your (other) external drive. You should see a list of folders representing the drives that are being backed-up. One is typically Macintosh HD, your internal hard drive. There should be one for your other external drive.

  • I keep getting error msg. 4 my lacie external drive that it unexpectedly quit. It then proceeds to go away and reappear again a ffew

    Hi All,
    Since I upgraded to ML, I keep getting error msg. 4 my lacie external drive that it unexpectedly quit. It then proceeds to go away and reappear again a few mins. will appear. It also mentions this ejection could destroy my data. I've already updated the Driver to the most current one ta LaCie had for my 500 GB Rikki External. That didn't help. I also tried Disk Utility to repair permissions No Help! Suggestions?

    That would be highly unusual, since the Apple ID is almost always the email address, unless it's changed later, and normally has to be unique to set up a new Apple ID. In any case, if you have two Apple IDs (or more), you probably need to authorize the computer using both.
    Regards.

  • I have a power pc (g5) computer that I will soon be replacing with a current i5 or i7 mini. How do I transfer the Time Machine files from the internal hard drive on the G5 to an external drive that I will later use with the Mini?

    I have a Power PC G5 computer that I will soon be replacing with a current i5 or i7 Mini. How do I transfer the Time Machine files from the internal hard drive on the G5 to an external drive that I will later use with the Mini?

    Hi, likely the easiest is to just poll the drive & get something like this...
    Get MacScan...
    http://www.apple.com/downloads/macosx/networking_security/macscan.html
    http://eshop.macsales.com/item/NewerTech/U3NVSPATA/
    But if you have a good external drive already, just clone it.
    Get carbon copy cloner to make an exact copy of your old HD to the New one...
    http://www.bombich.com/software/ccc.html
    Or SuperDuper...
    http://www.shirt-pocket.com/SuperDuper/

  • Is there a way to "force-mount" an external drive that doesn't show up on it's own when plugged in with firewire?

    Hi, is there a way to "force-mount" an external drive that doesn't show up on the desktop? I have a new Hitachi SATA III 2 TB Ultrastar that won't show up like all the other drives when plugged in. So I can't partition, repair, format etc with Disk Utility, Disk Drill, Tech Tools etc. How do I make it visible?
    I use the FW 400 to 800 adapter and a FW hub.
    Thanks,
    W.

    ok, I did find the log in Diskutil of what happened, I just can't figure out why it happened and how to start over:
    2014-04-20 13:42:08 -0400: Disk Utility started.
    2014-04-20 13:44:30 -0400: Preparing to erase : “Terra 8”
    2014-04-20 13:44:30 -0400:           Partition Scheme: GUID Partition Table
    2014-04-20 13:44:30 -0400:           1 volume will be created
    2014-04-20 13:44:30 -0400:                     Name                    : “Terra 8”
    2014-04-20 13:44:30 -0400:                     Size                    : 2 TB
    2014-04-20 13:44:30 -0400:                     File system          : Mac OS Extended (Journaled)
    2014-04-20 13:44:30 -0400: Unmounting disk
    2014-04-20 13:45:00 -0400: Creating the partition map
    2014-04-20 13:45:01 -0400: Waiting for the disks to reappear
    2014-04-20 13:45:01 -0400: Formatting disk2s2 as Mac OS Extended (Journaled) with name Terra 8
    2014-04-20 13:45:26 -0400: Initialized /dev/rdisk2s2 as a 2 TB case-insensitive HFS Plus volume with a 155648k journal
    2014-04-20 13:45:26 -0400: Mounting disk
    2014-04-20 13:45:29 -0400: Erase complete.
    2014-04-20 13:45:29 -0400:
    - That was it, gone.....

  • Moving iTunes library to an external drive that already has music on it?

    I want an external drive that contains music to be designated as my iTunes library. How do I do it?
    Note: I do not want to move an existing library to the external drive, just start fresh with the library on the drive.
    Thanks!

    pbay wrote:
    I want an external drive that contains music to be designated as my iTunes library. How do I do it?
    Note: I do not want to move an existing library to the external drive, just start fresh with the library on the drive.
    welcome to the discussion area, pbay !
    1) launch iTunes with the option key pressed. choose to create a new library when prompted.
    2) in preferences > advanced make sure iTunes is pointed to the external drive and that +keep iTunes media folder organized+ and +copy files to iTunes media folder when adding to library+ are checked.
    3) from the iTunes file menu, choose +add to library+ and start populating iTunes with the tunes you want.
    when you have added all tunes to your new library, make sure they play fine. right-click on random files and +get info+. look at the summary tab and check if the path leads to the correct location (your external drive).
    when satisfied, the original files can be deleted.
    happy computing ...

  • Is it possible to use one of the mac pro's internal hard drives as a external drive that can be accessed by a macbook etc?

    is it possible to use one of the mac pro's internal hard drives as a external drive that can be accessed by a macbook etc?

    Only if you move it to an external enclosure and let them both access it through a file server. 

  • HT2963 I have a 1 TG external drive that is formatted to Windows NTFS and is read only, how do i get it to read and write on my Mac OS X 10.6.3?

    I I have a 1 TG external drive that is formatted to Windows NTFS and is read only, how do i get it to read and write on my Mac OS X 10.6.3?

    Install software such as Paragon NTFS, or reformat it as Mac OS Extended (Journaled) or FAT32. Mac OS X 10.6.5 and newer can also read and write exFAT partitions.
    (97498)

  • Buying External Drive that Only Needs One USB Port?

    The optical drive on my 2007 MacBook Pro has been dead for about 6 months. I need to get an external one so I can install some software, but I am having trouble finding one that only uses one USB port, as there is only one on each side of my notebook. I went to Best Buy today, and the only one they had that is compatible with a Mac needs two side-by-side USB ports.
    Does anyone know of any good Mac compatible external drives that only require one USB port? I am interested in purchasing one by LaCie, but their site does not specify how many USBs it requires.
    Any advice you can give me will be greatly appreciated!

    Welcome to Apple Discussions!
    You might want to consider a FireWire powered optical drive:
    http://eshop.macsales.com/shop/firewire/optical-drives/
    A FireWire port will deliver more power, so you would only need to use one FW port. The people at OWC are very Mac knowledgeable and could help you to pick one out. Your 2007 MBP should have both FW400 and FW800, so you could use either port.
    Good luck!

Maybe you are looking for