What size drive for Time Machine?

Discussion in 'iMac' started by ifman, Dec 10, 2016.

  1. ifman macrumors member

    ifman

    Joined:
    Mar 30, 2011
    #1
    I just bought the Seagate 4TB backup drive for my new imac (27" 5K with 2TB). I only have about 500gb on the computer, which I transferred from my old PC. I'm retired, so I won't generate a lot of work files, but I do want to scan and digitize all the old family photos....I guess that may take some space.

    My question is....Will I want TimeMachine to use the full 4TB of the Seagate to make backups, or should I reformat the Seagate and partition so I can use 1 or 2 TB for regular file storage? In other words, do I need 4TB for endless TimeMachine backups.....or less? What is the normal setup?
     
  2. thats all folks macrumors 6502a

    thats all folks

    Joined:
    Dec 20, 2013
    Location:
    Austin (supposedly in Texas)
    #2
    the general rule is, double the size of the volume being backed up. this gives TimeMachine room to hold version history and deleted files as well as perform it's tasks. TimeMachine will just keep filling up the available space and dump the oldest versions as the drive fills up.

    question, if you have over a TB available on your main drive maybe just put your files there (and TimeMachine will keep the backed up). and, if you use part of your TimeMachine drive for general storage, where are those files backed up to? I'd leave a TimeMachine drive dedicated to just that task and get other drives if you need work or dump space.
     
  3. Weaselboy Moderator

    Weaselboy

    Staff Member

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    Jan 23, 2005
    Location:
    California
    #3
    No you do not. Most people suggest 2X the amount of data you have, so if you have around 500GB of data, a 1TB partition would leave you plenty of room for Time Machine versioning. Then you can use the other partition(s) for whatever you want.

    The only issue with that is if you have vital data on that second partition, it is not really being backed up anywhere since the Time Machine data is on the same physical drive. If you don't mind that, there is no problem making and using partitions.
     
  4. russtobin macrumors newbie

    Joined:
    Nov 1, 2010
    #4
    Another option is to use a caddy and hdd dedicated to the Imac. Beauty of the caddy is that you can use either 2.5 or 3.5 hdd which alot of people have just lying around. It's a good and inexpensive way of using redundant hdd.
     
  5. cynics macrumors G4

    Joined:
    Jan 8, 2012
    #5
    Time machine will eventually fill any size drive given enough time.

    Currently I have 623gb used on my iMac. My TM backup is 686. This dates back to March 22, 2016. So a 63 gb delta over ~8 months with my particular usage.

    I'm generally careful to keep my scratch work in a non backed up folder so I don't inadvertently fill up the time machine.

    Since I'm using a NAS I can add terabytes to my TM with a few clicks should it fill up. Highly recommend using a NAS for this and other various reasons (data redundancy).
     
  6. ivanwi11iams Contributor

    ivanwi11iams

    Joined:
    Nov 30, 2014
    Location:
    Kennesaw, GA
    #6
    ...you actually just gave me an idea. I have a 3TB SSD for my Time Machine. I might partition it, and then run my VMWare VMs, from there...
     
  7. protoxx macrumors 6502a

    protoxx

    Joined:
    Oct 10, 2013
    #7
    An SSD is kind of a waste for a backup drive. Better to spend that money on multiple back drives that can be swapped.

    Anything that is on the same drive as your backups is by definition at risk. If your backup drive fails you also lose anything on any other partition.

    Best to have backup drives being single use items. Better to have a second one and swap out occasionally. Keep one at office/family members home/safety deposit box as a disaster recovery. If you house burns down or thief breaks in and takes both system and attached drives.
     
  8. maflynn Moderator

    maflynn

    Staff Member

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    May 3, 2009
    Location:
    Boston
    #8
    Where will you back up your VMs from?

    As for using SSDs for backing up, I'd not use them for that purpose
     
  9. ivanwi11iams Contributor

    ivanwi11iams

    Joined:
    Nov 30, 2014
    Location:
    Kennesaw, GA
    #9
    Oops, good point about VM backups...!
    Back to the drawing board, leaving all as is
     
  10. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #10
    I back up my VMs outside of TimeMachine because they can clog up your backups, because as you use the VM, they'll be flagged for backup, every hour. I exclude them, and them and back them up on a different volume.
     
  11. MacDawg macrumors Core

    MacDawg

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    Mar 20, 2004
    Location:
    "Between the Hedges"
    #11
    I do as well, otherwise TM will fill up quickly and defeat your purpose
     
  12. ivanwi11iams Contributor

    ivanwi11iams

    Joined:
    Nov 30, 2014
    Location:
    Kennesaw, GA
    #12
    Brilliant tips about VMs and Time Machine backups!
     

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