How does time machine work with an external HDD?

Discussion in 'Mac Accessories' started by RetepNamenots, Aug 5, 2009.

  1. RetepNamenots macrumors 6502

    May 30, 2009
    Hi, I was wondering how time machine would work with an external hard drive.

    I need an external drive so that I can make sure that my work is backed up; I believe that Time Machine takes a new backup each time a file is edited?

    Anyway; does the external drive have to be partitioned or formatted in any particular way for time machine to function?

    I ask because I would like to use my external drive to store games and music (as a backup, not a primary source), but also be able to use it with time machine.

    Also, does time machine make a copy of the entire mac drive, or does it just backup specific folders (such as your user areas). If so, can I select these myself?

    Finally, does anyone have any recommendations they could give me for a good external, portable HDD? I have only looked at Seagate's lineup so far. I am willing to spend around £60 - £70 or so.

  2. thegoldenmackid macrumors 604


    Dec 29, 2006
    dallas, texas
    It just has to be able to work with OS X in terms of formatting. Time Machine will then just work with it.

    As far as hard drives, I would go with whatever your needs. If you find yourself only backing-up, I'd go with just a regular A/C powered-one versus the portable.

    After Taking Part in Numerous Threads and Purchasing Numerous Drives after Research, I have come to a couple of suggestions and a massive "guide."

    There are three (basic/main) parts to the speed of your external drive:
    1. Connection Type – This is the one most people will know about, if they know one. Things like Firewire 800, Firewire 400, USB 2.0, eSata, etc. It comes to how your drive connects to the computer, in general (fastest to slowest) eSata, Firewire 800, Firewire 400, USB 2.0. Firewire is preferable because it is not only faster then USB, but it transfers at a constant speed, whereas USB is variable. eSata is the fastest but it requires a port that is not available without an adaptor, and those adaptors are hit and miss in terms of quality. Chances are most users will do fine with Firewire 800 and have no need for eSata.
    2. Hard Drive Speed – For some reason people seem to forget that if you have 4200 RPM Drive inside your enclosure, it's going to be slow. This depends on the physical drives inside your enclosure. Speed from fastest to slowest: SSD, 7200 RPM, 5400 RPM, 4200 RPM. The higher the revolutions per minute, the faster, unless there are no revolutions at all ;).
    3. Cache – The one people forget. The cache is just like your computer stores the information temporarily. It is important that if you look at this, especially if you are going to try to play files from your drive. Even if you are using it is a back-up, you don't want a 4MB Cache. Higher the cache the better; 64MB is the general highest speed for most stock drives.

    Or you could be OCD, anal and paranoid like me and have two back-up drives...

    Other User's Recommendation's:
    Build Your Own: uberamd, kufford, SaSaSushi, nanofrog, Ti_Poussin
    Drobo: gatepc recommends it, further mixed discussion here.
    EZQuest: LizKat has owned a variety of Monsoons
    G-Tech: RebornKillah recommends the G-Drive Quad 500GB, but it's currently out of production; Digital Skunk notes the great warranty; jaysmith recommend G-Tech
    Hitachi: Trag (SimpleTech Signature Mini 500GB); Thedesolateone also recommends Hitachi.
    Iomega: mc3s (Ultramax 34495 1.5 TB); Justin Lee (eGo 500GB Portable Mac).
    ioSafe: Tterb recommends.
    LaCie: Note: there is an entire thread dedicated to LaCie, I have summed up support from users below, but simply a tally
    jrotunda85, (d2 Quadra 1 TB); RedTomato, gatepc & eVolcre, {although eVolcre owns the one with eSata and Firewire 400}(Hard Disk, Design by Neil Poulton 1 TB); iGary (LaCie Rugged); Gymnut (F.A. Porsche, out of production); VanMac (BigDiskExtreme, out of production); Digital Skunk (2Big Triple, out of production)
    Users expressing general support: cmcbridejr, dpaanlka, LethalWolfe, mpsrig, UltraNeo*, iPhoneNYC, chocolate632, Hellhammer, romanaz
    Users not so happy with LaCie: surfmadison (not a big fan), accacc57, dave12345 (Little Disk), jaysmith, Jerkfish, auero, mperkins37, dfs & jessica.
    Maxtor: adamvk purchased a OneTouch 4 1TB (not sure what version)
    Seagate: steeler (FreeAgent Desk 1.5 TB); MacMini2009, rick3000 (Seagate FreeAgent Desk 1 TB USB Mac); Acid303 does not recommend the (new) Seagate FreeAgent Desk series
    SimpleTech: J&JPolangin (SimpleTech 2TB SimpleDrive Pro Duo); BlizzardBomb recommends the Go; suekitch recommends Seagate because of its warranty
    Western Digital: MacMini2009, xpress1 & MacDawg (MyBook Studio 1TB); Thiol notes purchasing an incredible seven Western Digital MyBook Studio drives all working flawlessly; Acid303 also notes a positive experience with a non-Studio Edition Western Digital drive; terp2007 & matthewscott661 recommend the Passport Series; munkees notes a failure with one of the drives purchased, but a positive experience overall; rikdiddy, RebornKillah & Jerkfish also recommend Western Digital. chrono1081 does not recommend Western Digital & romanaz was also not happy.

    Other Threads:

    1TB is prbly a good size to start at it, I would say most people looking for non-mobile externals start at that size, here is a (not-so) recent thread about that...
    More literature found here.
    Here, is another thread on 1TB Hard Drives
    This one is about LaCie...
    Here is another, there is some more discussion about LaCie in there...
    Here is one on USB 1TB, I'd stick to Firewire...
    And if all else fails, MRoogle
  3. spinnerlys Guest


    Sep 7, 2008
    forlod bygningen

    Time Machine (TM) makes a backup every hour. After one day of backing up it will be stored as one day.

    For example:

    It's Monday, January the 5th, 12:30pm.

    The last backup happened 12:29pm and you can access 24 backups for the last 24 hours, back to Sunday the 4th, 1:29pm. But on Wednesday, January 7th, you will see the 5th only as one backup for one day, not as 24 backups.

    Also, the drive needs to be formatted in HFS+ (Journaled) to properly work with TM.
    It would be best to partition the external drive, one volume/partition for TM and the other for your manual backups.

    TM will backup every file of your internal drive, unless you exclude specific folders/volumes/drives it via TM preferences.


  4. RetepNamenots thread starter macrumors 6502

    May 30, 2009
    Thanks for the reply.

    After looking at the description (wikipedia!), I've found out how Time Machine works. I guess I can partition the external drive to have 100Gb for music and games, for example, and the other 400Gb dedicated to time machine.

    I understand completely what you're saying about not paying too much attention to the bad experiences that others post about. It's often those who have problems who shout the loudest; whereas those who have no problem have no reason to complain!

    I'm going to just go with a 500Gb drive; I have a 500Gb HDD in my MBP, but am only using 68GB on my OS X partition.

    I take it I can just buy any external 'PC' drive, and format it to OS X Extended (Journaled) and all will be well?

    Thanks again

    Edit: Thanks also for your reply, spinnerlys. I took a while writing my reply whilst doing more research!

    But that helps clear the rest of my questions (above) up nicely!
  5. spinnerlys Guest


    Sep 7, 2008
    forlod bygningen
    Yes, you can buy any HDD and format it with HFS+.

    But know, that those 500GB drives have "only" 465GB of real storage (or 465Gibiytes/GiB).

    Also your signature has a little error: 1Tb (2x500Mb) - 1TB (2x500GB)

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