external HDD & Thunderbolt added value???

Discussion in 'iMac' started by exatik, Jul 16, 2016.

  1. exatik, Jul 16, 2016
    Last edited: Jul 21, 2016

    exatik macrumors newbie

    Joined:
    Jul 16, 2016
    Location:
    Brussels
    #1
    Hi all,

    Context
    I recently bought an iMac 27' with 512 GB SSD internal drive. Mainly to be used for photography workflows (Lightroom & Photoshop). I am now looking for an external storage solution to manage the photo library, and let the internal SSD take care of catalogs and applications. I also keep in mind that the chosen storage solution will impact the backup strategy (to set up). A capacity of 4 TB storage will cover my needs. As you may know, the late 2015 iMac includes (2X) Thunderbolt 2 ports and (4X) USB 3.0 ports

    The first choice goes to external spinning hard drive(s) as no high speed transfer is required in my case (no work on video files expected), and for price reason.

    I have seen lot of interesting threads and articles, however the question remain the same to me:

    The question?
    if I plug an external spinning drive, as a standard of 64MB cache, 7200RPM, no RAID..., what is the real difference to use the Thunderbolt port against USB 3.0 port ?

    Why this question?
    - The transfert rates for ports : USB 3.0 = 5GB/s, Thunderbolt = 10GB/S, Thunderbolt 2 = 20GB/S
    - The transfert rates for external spinning drives are around 160-240 MB/s. As for example G-Drive with Thunderbolt 4TB is 245 MB/s and G-Drive G1 4 TB USB 3.0 is the same 245 MB/s (6 TO disk).

    What does it mean?
    - Using an external HDD, Thunderbolt would have no added value to go for, as the spinning drive will be the bottleneck of the chain, bringing 245MB/s max of transfer rate versus 10GB/s proposed by this port...
    - Thunderbolt ports could be used with SSD external drive to allow better read/write rate. For instance, I see SSD performs around 450 MB/s (no raid)...Which is still below the 10-20 GB/s proposed by TB.

    Need your help
    Am I correct to benchmark ports against drives transfer rates?
    Please let me know which storage solution you would recommend to me. What would be your advice for an associated backup strategy?
    Is there any difference between TB and USB 3.0 in real world, using external HDD or external SSD?

    Many thanks beforehand!
     
  2. komatsu macrumors 6502

    Joined:
    Sep 19, 2010
    #2
    Don't get too caught up on transfer speeds, redundancy should get more of your attention!

    If you have just 1 x 4TB external hdd and it fails, you could loose a lot of data.

    You need redundancy. Hence, why I would recommend that you get a Synology NAS with 2 x 4gb drive configured in
    RAID 1. Therefore, if one disks fails, you still have a backup.
     
  3. exatik thread starter macrumors newbie

    Joined:
    Jul 16, 2016
    Location:
    Brussels
    #3
    Thanks komatsu.
    The Sinology NAS seems indeed to be a wise solution to archive the data. However for storage purpose, I would prefer not to be limited by Gigabit transfer speed even though theoretically it can reach around 125MB/s maximum. I heard the ethernet transfer speed with NAS is not as fast as HDD connected in USB 3 or Thunderbolt.

    I am not looking for the fastest storage solution, but for the most appropriate as I will need to access my photo library and work on it.
     
  4. komatsu macrumors 6502

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    Sep 19, 2010
    #4
  5. chabig macrumors 68040

    Joined:
    Sep 6, 2002
    #5
    Many Synology units have USB 3, and other products (Drobo) are available with Thunderbolt and USB 3 as well. If the unit is going to be directly attached to your Mac, you probably don't need ethernet.
     
  6. komatsu macrumors 6502

    Joined:
    Sep 19, 2010
    #6
    Great suggestion about Synology USB 3.0. I was forgetting about that.

    As for Drobo, these can be a right PITA if something goes wrong with RAID.
     
  7. exatik thread starter macrumors newbie

    Joined:
    Jul 16, 2016
    Location:
    Brussels
    #7
    Thanks again for your replies.

    Are you suggesting to use a NAS Synology as an external hard drive, via the USB 3.0 port?
    I am not sure if the NAS would allow this type of connection. The NAS appears to be an independent unit attached to the network via ethernet/Wifi. By reading the Sinology specs, USB 3.0 ports aims to backup the NAS unit or to transfer data on it. Not sure about the read and write operations coming directly form the Mac.
    I see a great opportunity to setup a RAID storage thanks to a NAS, but for the time being, I don't have the need of sharing media files or create a home cloud.

    As you mentioned I was also looking at this G-Raid with Thunderbolt 8 TB. A bit pricy here in Europe, and I don't see the possibility to change the hard disk directly from the removable disk module.

    Then I have seen this G-Drive with Thunderbolt & USB 3.0, 4 TB:
    http://www.g-technology.com/products/g-drive-thunderbolt

    And this G-Drive G1 USB 3.0, 4 TB:
    http://www.g-technology.com/products/g-drive-usb

    Which led me to raise the question about the transfer rates.
    What is the real difference between USB 3.0 and Thunderbolt when using an external spinning hard drive ?

    If there is no RAID or/and no external SSD to be used, Thunderbolt do not perform better than USB 3.0, am I correct?
     
  8. maflynn Moderator

    maflynn

    Staff Member

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    Boston
    #8
    There's been benchmarks showing that USB 3.0 is as fast as TB, given the high price of Thunderbolt accessories, I'd look for USB 3.0 unit.
     
  9. exatik thread starter macrumors newbie

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    Jul 16, 2016
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    #9
    To support your post, following a few investigations on the internet, it looks indeed the TB do not bring added value compared to USB 3.0 (spinning drive, no RAID). G-technology itself even reports 165MB/s max speed transfer for both G-drive USB 3.0 model and for the TB+USB 3.0 model.

    Then I would go for two G-drive 4TB USB 3.O.
    http://www.g-technology.com/products/g-drive-usb

    The first one to store 3,5 TB + Backup of the iMac 512GB internal SSD.
    The second one to clone this G-drive 4TB.

    Does it sound appropriate to start with my workflow?
     
  10. maflynn Moderator

    maflynn

    Staff Member

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    #10
    Yes, and its good to consider the backup needs of the external drive as well.
     
  11. exatik thread starter macrumors newbie

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    Jul 16, 2016
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    #11
    I see in your signature you own a late 2015 5K iMac. May I ask you what do you personaly use for external storage and backups? Have you opted for a full internal SSD as well?
     
  12. maflynn Moderator

    maflynn

    Staff Member

    Joined:
    May 3, 2009
    Location:
    Boston
    #12
    I use a Drobo Mini for my Time Machine backup, it was my main external drive holding my music and other data that did not fit on my MacBook Pro when I used that as my primary machine.

    I also have a number of other external drives, that I use for Carbon Copy Cloner images, and I also run different versions of OS X for testing purposes.
    --- Post Merged, Jul 19, 2016 ---
    As for my internal drive, I have a 2 TB Fusion drive as I found the cost of a large SSD to be beyond my budget. As it stands, I'm not using much of the space, but I'm very happy with the performance.
     
  13. exatik, Jul 21, 2016
    Last edited: Jul 21, 2016

    exatik thread starter macrumors newbie

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    #13
    I received the G-Technology G-drive USB 3.0 4TB.
    http://www.g-technology.com/products/g-drive-usb

    Here are the speed test results:
    G-Drive G1 USB 3.0.png

    The speed is very close to the specs announced by the manufacturer (165MB/s). Apparently, this is really good for an USB 3.0 HDD. Thunderbolt port being useless to run with spinning drives, if no RAID.

    The pros:
    - quite quiet for a spinning drive
    - Real transfer rate close to specs
    - Price & design

    The cons:
    - The alu block of this external drive is significantly warm. I am wondering whether it could be a working storage drive (as it needs to be daily on) or only to be used as a backup drive.

    Any experience to share?
    --- Post Merged, Jul 21, 2016 ---
    Please also note USB 3.0 is theoretically 5 GB/s transfer rate.

    So we are very far from the real world performance which is 165 MB/s max in my case, with above mentionned HDD ...
     
  14. cynics macrumors G3

    Joined:
    Jan 8, 2012
    #14
    It will be fine. I used an external 2.5 HDD plugged into an AirPort Extreme for years and it was warm/hot the entire time. It never slept (I didnt investigate to see if that was normal or not) so it was always on. I now use that drive as an off site backup for some relatively important data.

    A mechanical HDD generates heat (well even SSD do to some extent) but as long as its ventilated (not wrapped up in a blanket) it should be fine.

    Currently I have 2 3tb HDD's in a synology NAS and at idle they are hovering around 90 degrees F.

    Screen Shot 2016-07-21 at 10.01.38 AM.png

    And that is with a fan in the enclosure running at a medium setting.

    BTW as far as NAS units go you can use what is called 'link aggregation' (2 x gigabit ethernet) to increase its transfer rates on most modern NAS units. I find it unnecessary for my usage but doing that will greatly increase transfer speeds and even more so if you have the drives setup in RAID 0. Just kind of a future reference thing.
     
  15. exatik thread starter macrumors newbie

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    Jul 16, 2016
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    Brussels
    #15
    Thanks for your share of experience.
    I should keep this drive on and see how it goes. The plan is to make a backup of it, using another 4 TB G-Drive.

    The NAS is an option I will definitely consider in the very next future, as a second and local backup. Good to know about this ethernet link aggregation.

    I am still surprised by the real world transfer rates versus the ones specified for the iMac ports (USB 3.0=5GB/s, TB=10GB/s, TB2=20GB/s). This is far from what we can get as end users. To me, that makes discussions around USB 3.1 (40GB/s) quite useless, as today no drive can assume such a speed. SSD external drives speed being around 450-700 MB/s max... It means USB 3.0 port rocks!
     
  16. joema2 macrumors 65816

    joema2

    Joined:
    Sep 3, 2013
    #16
    I have many USB 3.0 and Thunderbolt drives, some RAID. You are correct there is generally not a performance difference on the lower end. I have several two-drive RAID-0 units, some Thunderbolt and some USB 3.0. They perform about the same. For RAID-0 there is a difference between built-in AppleRAID vs SoftRAID, and SoftRAID is faster (whether USB or Thunderbolt). This may also apply to RAID-1 but I have not tested it: https://www.softraid.com/

    A significant limitation of USB drives beyond 2TB is a Mac cannot boot from them. So if you are making a clone backup and want to boot from that drive, it must be Thunderbolt.
     
  17. roadkill401 macrumors 6502

    roadkill401

    Joined:
    Jan 11, 2015
    #17
    Your question is about two different things.

    1. A backup is just that. Backup! you have all the data still on your local drive and the backup is a second copy of that data just in case the local drive fails, you don't loose anything. If the backup drive fails, then you replace that drive and re-copy what is on the local drive.

    What many however do is use the backup drive as being an ARCHIVE as well. Where you are putting data that is not stored anywhere else. in that case, you definitely need redundancy on the drive as it is a single point of failure. You backup needs to be as large as the data that you are trying to store on it. if your local drive is only 512gb, then 4tb of drive space is dramatic overkill. Unless you are attaching external storage to your system thus increasing the amount of data to be backed up. But i don't think that TimeMachine will backup external drives.

    2. Dont mix Backup with external storage. It makes no sense to backup your data on the same drive you are storing on. that only solves if you accidentally delete a file as long as that file was part of a previous backup.

    I have a cheap old Synology DS209 that is functionally obsolete for using as network storage but perfect for a time machine backup drive. I have it with 2x2tb (slow) drives mirrored. They just happened to be some drives I had laying around not in use for anything. It doesn't matter if it's slow in performance as it's just for that one backup purpose. The Synology is tucked away in another part of the house so if heaven forbid the house is broken into and they steal my iMac, the backup will likely not get taken as well.

    I keep my external storage on a Thunderbolt drive. I'd recommend that you not cheap out on yourself and buy a thunderbolt enclosure and add your own drives to it. I say get an OWC Thunderbay and add in some SSD drives as you need them. Then you get some decent speed and the option to expand or add redundancy if you want to.
     
  18. cynics macrumors G3

    Joined:
    Jan 8, 2012
    #18
    I'm not trying to nitpick your post because I mostly agree. But it should be mentioned the size of the back up drive in reference to the size of the drive its backing up is irrelevant if you are using Time Machine. Given enough time a 512gb drive will fill a 4tb drive.

    More of a side note but if you deal with very large files for editing purposes I recommend setting a folder that isn't backed up via Time Machine you can quickly fill up the back up and it will start purging older maybe more important information. I've accidentally filled 3 tb with 30gb+ MKV's and it wasnt until I actually needed the back up that I found I didnt have the info I was looking for.
     

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