jszrules

Q: Airport Disk: speed and Time Machine questions

Hi, my Time Machine volume has always been a USB-connected external drive. I recently purchased the latest Airport Extreme, partly because of its ability to use an Airport Disk as a wireless Time Machine drive. When I connected the drive to AE, it tried to perform a backup (as a sparse bundle?) as if it were a new backup and not incremental to what was already on the drive. So I gave up and reconnected it via USB, and even then I had to delete the half-created sparse bundle before my machine backed up incrementally again. Here are my questions:

 

1) Is there a way for Time Machine to recognize that the drive is the same regardless of whether it is connected via USB or Airport Extreme? I hoped that TM would be smart enough to do this. It's the same drive, just connected in a different way!

 

2) I noticed the speed of reading files off an Airport Disk was slow, even the latest generation. Is this expected? Of course I don't expect it to be as fast as USB, but this was noticeably slow. Any way it can be improved?

 

3) Finally, a more theoretical question taking into account the first two questions. As Apple does away with ports on its MacBooks, I would assume the need to wirelessly connect to external drives with decent performance becomes essential (for Time Machine, but also for basic data storage). Time Capsule is not a portable device, so I think using a portable external HD as your TM backup has its advantages over Time Capsule. Am I missing something? I find it strange that a "port-less" laptop can only backup via a non-portable Time Capsule or a very slow and unintelligent Airport Disk. Is iCloud supposed to be the eventual answer for all of this, making Time Machine irrelevant in the near future? 

 

Thanks

MacBook Pro with Retina display, OS X El Capitan (10.11.1)

Posted on Oct 26, 2015 9:16 AM

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Q: Airport Disk: speed and Time Machine questions

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  • by Tesserax,Helpful

    Tesserax Tesserax Oct 26, 2015 8:17 PM in response to jszrules
    Level 9 (53,940 points)
    Wireless
    Oct 26, 2015 8:17 PM in response to jszrules

    1) Is there a way for Time Machine to recognize that the drive is the same regardless of whether it is connected via USB or Airport Extreme?

    Sorry, but no. The format of the Time Machine backup will be different when connected in either of these two methods. This is as designed.

    2) I noticed the speed of reading files off an Airport Disk was slow, even the latest generation. Is this expected? Of course I don't expect it to be as fast as USB, but this was noticeably slow. Any way it can be improved?

    Yes, this is expected. Please check out the following AirPort User Tip for additional details.

    3) Finally, a more theoretical question taking into account the first two questions. As Apple does away with ports on its MacBooks, I would assume the need to wirelessly connect to external drives with decent performance becomes essential (for Time Machine, but also for basic data storage). Time Capsule is not a portable device, so I think using a portable external HD as your TM backup has its advantages over Time Capsule. Am I missing something? I find it strange that a "port-less" laptop can only backup via a non-portable Time Capsule or a very slow and unintelligent Airport Disk. Is iCloud supposed to be the eventual answer for all of this, making Time Machine irrelevant in the near future?

    No, I don't think that you are "missing something." ... and you make a good argument. Time Machine, currently, can only back up to the following types of devices: 1) Time Capsule (via Ethernet or wireless), 2) An external USB or firewire hard drive, 3) An AirPort Disk, 4) An OS X server, or 5) A Time Machine-enabled NAS.

     

    Your point about iCloud or any other cloud service as a potential option and may be the direction for the future.

  • by Bob Timmons,Helpful

    Bob Timmons Bob Timmons Oct 26, 2015 8:17 PM in response to jszrules
    Level 10 (104,968 points)
    Wireless
    Oct 26, 2015 8:17 PM in response to jszrules
    1) Is there a way for Time Machine to recognize that the drive is the same regardless of whether it is connected via USB or Airport Extreme?

    No, since Time Machine backs up differently to an external drive than it does to a network drive like a Time Capsule or a drive connected to the USB port of an AirPort Extreme.

     

    Time Machine back ups go to a normal folder called Backups.backupdb on a drive connected directly to a Mac. However, Time Machine backs up to a special container called a sparsebundle file or sparsebundle image on a network drive. So, when you connected the drive to the USB port on the AirPort Extreme, that drive became a new network drive. Time Machine saw a "new" drive that it had not ever seen before, so it started a new backup.

     

    Bottom line....it is not possible to swap the drive back and forth from an external to network location and use the same set of backups.

     

    2) I noticed the speed of reading files off an Airport Disk was slow, even the latest generation. Is this expected? Of course I don't expect it to be as fast as USB, but this was noticeably slow. Any way it can be improved?

    Couple of issues here. The first would be that the USB drive on the AirPort Extreme is only USB 2.0....quite a bit slower than  a USB 3.0 drive. Second, the signal processor in the AirPort Extreme is much slower than a USB processor on a Mac.

     

    Bottom line.....backups to a USB drive connected to an AirPort Extreme will occur at about half the speed of a USB 2.0 drive on a computer. Another way of saying the same thing is that backups will take about twice as long as normal with this type of setup. A Time Capsule would offer a much faster backup option with an Ethernet connection, and probably wireless as well, assuming a good connection since there is a SATA drive on the Time Capsule.

     

    3) Finally, a more theoretical question taking into account the first two questions. As Apple does away with ports on its MacBooks, I would assume the need to wirelessly connect to external drives with decent performance becomes essential (for Time Machine, but also for basic data storage). Time Capsule is not a portable device, so I think using a portable external HD as your TM backup has its advantages over Time Capsule.

    Well, if your Mac has a Thunderbolt port, you can connect to the Time Capsule using Ethernet by using a Thunderbolt to Ethernet adapter. That is as fast as backups can occur to a network drive like the Time Capsule. Or, if you are able to connect a drive directly to the Mac, then you can use USB 3.0 or FireWire for speedy backups. A Thunderbolt drive could be used of course, if your budget permits.


    Wireless can used as well, of course. Wireless can actually work quite well on "incremental" backups to a Time Capsule, assuming that you make the first "master" backup using a wired connection to speed things along.

     

    I find it strange that a "port-less" laptop can only backup via a non-portable Time Capsule or a very slow and unintelligent Airport Disk

    You might not have thought about the Thunderbolt to Ethernet option. In my case, I use a Mac laptop connected to a Mac monitor with a Thunderbolt connection, so any backups on the Mac and other copies as well, occur over Ethernet to the Time Capsule.  If I did not have the Mac monitor, I would use a simple Thunderbolt to Ethernet adapter when I had a big back up to copy over. . Thunderbolt to Gigabit Ethernet Adapter - Apple

     

    Is iCloud supposed to be the eventual answer for all of this, making Time Machine irrelevant in the near future?

    One of the problems with theoretical questions is that the answers will be theoretical as well. We are all users here....just like you.....and none of us here knows what Apple is thinking or what they will do.

  • by jszrules,

    jszrules jszrules Oct 26, 2015 11:28 AM in response to Bob Timmons
    Level 1 (5 points)
    Mac OS X
    Oct 26, 2015 11:28 AM in response to Bob Timmons

    Thank you both for the helpful responses.

    Well, if your Mac has a Thunderbolt port, you can connect to the Time Capsule using Ethernet by using a Thunderbolt to Ethernet adapter. That is as fast as backups can occur to a network drive like the Time Capsule. Or, if you are able to connect a drive directly to the Mac, then you can use USB 3.0 or FireWire for speedy backups. A Thunderbolt drive could be used of course, if your budget permits.


    Wireless can used as well, of course. Wireless can actually work quite well on "incremental" backups to a Time Capsule, assuming that you make the first "master" backup using a wired connection to speed things along.

     

    If I used the Thunderbolt-to-Ethernet option on my Airport Extreme+Airport Disk setup, would I be able to go back and forth from wireless to ethernet without Time Machine thinking it was a new backup each time? Also, would Airport Extreme+Airport Disk see the same improvement in speed that you mention above when using Thunderbolt-to-Ethernet on Time Capsule? Thanks again.

  • by Bob Timmons,Solvedanswer

    Bob Timmons Bob Timmons Oct 26, 2015 12:08 PM in response to jszrules
    Level 10 (104,968 points)
    Wireless
    Oct 26, 2015 12:08 PM in response to jszrules
    If I used the Thunderbolt-to-Ethernet option on my Airport Extreme+Airport Disk setup, would I be able to go back and forth from wireless to ethernet without Time Machine thinking it was a new backup each time?

    Yes

    Also, would Airport Extreme+Airport Disk see the same improvement in speed that you mention above when using Thunderbolt-to-Ethernet on Time Capsule?

    No, for the reasons that we already detailed above.

     

    The USB port on the AirPort Extreme is only USB 2.0 and the USB processing in the AirPort Extreme further limits that to half speed. In non-technical terms, USB on the AirPort Extreme is a huge bottleneck.

     

    Sorry to be blunt, but if backup speed is important to you, then the AirPort Extreme and an attached USB drive would not be for you.