Answers to Time Capsule reader questions

Following our introduction and teardown of Time Capsule, we were deluged with questions from readers about the product and how it works. Here's what we've found, along with some discoveries reported by readers.

An in-depth review of Apple's 802.11n AirPort Extreme Base Station

Apple Time Capsule unboxing and preview

A Look Inside Apple's New Time Capsule

Fast and Direct Access to the Time Capsule Drive

Andy M asks: "Can the TC unit be used as a 'hard wired' external drive either by connection with USB or Ethernet? In this hard wired mode can the TC be used to read and write data like a normal external hard drive? The 'hard wire' connection may be needed to speed up large file transfer or in the event that the AirPort (WiFi) connection is unavailable for some reason."

There's no way to put Time Capsule into anything like FireWire Target Mode, but if you want to connect to the drive faster than wireless networking will allow, attaching a computer directly to its Gigabit Ethernet port will provide very fast connectivity approaching the same speeds as a directly attached USB attached disk.

The unit can also be opened and the drive can also be removed and attached directly via SATA, but this is not trivial nor convenient to do. A Look Inside Apple's New Time Capsule shows how to open the unit up to access the drive.

"Can the TC be used as a normal external hard drive to store data? In other words can I manually drag files and folders to and from the TC (when it is connected wirelessly or when 'hard wired')."

Yes.

"If one has the TC close to ones main computer, would you recommend keeping it permanently connected by USB or Ethernet cable to improve the data transfer rate. In my case the wireless capability would only be needed for other computers or laptops in the house."

Gigabit Ethernet is indeed much faster than WiFi, yes.

"Can you tell me how loud Time Capsule is? Our network hub is in the kids room and I want to make sure that the fan to cool the disk is not loud and noisy."

Time Capsule is virtually silent. I can only hear the drive running if I have the unit in contact with my ear. It runs slightly warmer than Apple TV. It has a 30 watt power adapter, meaning that it doesn't use that much electricity though the drive is running all the time.

Partitioning the Time Capsule Drive

"Can the TC be partitioned like a normal external hard drive? If so how big a partition should one allow for Time Machine backup? I guess this also raised the question: Is it necessary or desirable to partition large capacity hard drives?"

The Time Capsule software does not provide any support for partitioning the drive, but has no problem dealing with partitions on the drive. That means you'd have to remove the drive and partition it yourself. Many readers asked about partitioning, but for most users, there isn't really any good reason to partition the disk, as it would only create artificial barriers to using the drive.

That doesn't mean some users won't try. Aaron of computerserviceman.com reports that it's possible to remove the drive and partition it:

"I read through many of the posts since Time Capsule was announced and never could I find anyone who was able to or knew if you could partition the internal hard drive in Time Capsule. Therefore, when I received the beauty on my door this morning, I opened Time Capsule, connected the drive directly to my mac via USB SATA Hard Drive Cables and took a look at what was on the drive. There is a partition for the Apple Airport Settings, a partition for the Apple Airport Swap File, and the third partition where all your data goes.

So first thing I did was use disk utility to make a backup of the current configuration in case my drive were to ever fail. Then I proceeded to resize the DATA partition to suite my needs of my 3 macs.. (630GB) and left the rest for use as a NAS Space (300GB). I put the drive back into Time Capsule turned it on and crossed my fingers. Just as I thought, it worked. When using Time Capsule install disk it shows two partitions: Data & Data_2 (below)."

Complex File Permissions

David W., in Boston asks: "Does the Time Machine support partitioning into two separate volumes with separate password protection (to facilitate two users mounting their own independently password-protected volumes on the drive)?"

No, even if you add your own partitions to the internal drive, there is no mechanism for using different passwords to secure different volumes. This also applies to adding external USB drives; there is only one password for all the shared drives, and no provision for setting up complex folder permissions. This is the same as disk sharing on AirPort Extreme.

Jose B. similarly asks: "I would to know if I can set shared folders on the Time Capsule Hard Disk, with restricted permissions (some users can read, some users can r&W, etc).... Would this be possible with Time Capsule?"

Yes, in addition to setting up a single password for all users, both Time Capsule and AirPort Extreme allow you to define a list of users, and assign each read only or full read and write permissions. However, there is no more granular controls to set up drop box (write only) permissions or to define different permissions on different volumes, files, folders or drives.

Reigning in Time Machine

The only significant difference in how Time Capsule works compared to AirPort Extreme is that the new unit supports being used by Time Machine for backups. AirPort Extreme does not currently support being used as a backup target by Time Machine, although it can be hacked to bypass the restriction. Officially supported use with Time Machine would apparently require a firmware update to the Extreme, and Apple is being coyly quiet about whether or not this is in the works.

Theo K asks: "Can you control how much space Time Machine uses of your Time Capsule, so you could say I would like to use 200Gb for Time Machine, and 300 Gb for file sharing in general. I have heard that Time Machine uses all your available space on your drive, so basically you could end up with 500gb of Time Machine backups, and be left with no room for file sharing.""

Time Machine will indeed eventually use up all the disk space available, and there isn't any way to set it to only use a specific amount of disk space. Attaching an external drive would provide a natural barrier to separate the disk used by Time Machine and the disks used for general file sharing. Apple has recommended using Time Machine on a volume that is only used for sharing. Manually partitioning the drive would be another option, but users can also just occasionally check their drive to make sure they haven't lost 500GB to backups.

Lance Gilbert asks: "Can the Time Capsule be set up to use its own internal drive as a backup and then switch over to the external drive once the internal drive is full? In other words, can both the internal and external drive be combined for use as backup drives?"

There is no automatic fall over system, but users can switch Time Machine to point to the new external drive after filling up the internal volume were that to occur, leaving the backups on the internal disk intact as an archive and available for later retrieval. Time Machine can return to a previously used volume to restore files.

Time Machine File Portability and Disk Image Experimentation

David K. asks: "Please include how/if one can transfer existing Time Machine backup files from another hard drive to Time Capsule."

If the existing backups were made to a local drive, this wouldn't be practical, as local and network drives use different file structures to save Time Machine data. Once a drive has been used with Time Machine, it's best to either retain it as an archive, or choose to wipe the drive for reuse. The files on it are not really designed to be portable.

Mr L. in the UK asks: "Early reports suggest the Time Capsule uses a sparse 'expanding' partition to store Time Machine backups. Theoretically, this would continue to expand until the disk is full. Could you see if it is possible to 'limit' how much of the drive that Time Machine can use up, by creating a read/write disk image (say, 250gb) and placing that onto the Time Capsule drive?"

Partitioning the disk or using an additional external USB drive would probably be better ways to accomplish the same thing. Trying to force Time Machine to use a rigid sparse image constraint may result in lost backups, which would not be a good thing.

Back to My Mac in a Time Capsule

"Can the drive be mounted at-will, and used as a regular network-attached drive for drag-and-drop storage?"

Yes.

"Can the drive be accessed over the internet, e.g. using a MacBook away from home to browse a documents folder on the Time Capsule drive?"

Yes, it supports Wide Area Bonjour, the basis of Back to My Mac. However, Apple hasn't made it obvious how to connect the device to its .Mac servers in order to do this. Savvy users with access to their own DNS-SD server will be able to set this up themselves, but the rest of us will need to wait for Apple to make things more obvious.

Both Leopard and Time Capsule allow users to enter a Hostname, User, and Password for a "dynamic global hostname," which means creating a Wide Area Bonjour name that can be looked up by Back to My Mac from any location. This panel (below top) is brought up by clicking Edit next to the Time Capsule Name (below bottom), or in Leopard, by clicking on Edit next to the Computer Name in System Preferences : Sharing.

There's no clue how to set this up provided by Apple, but it appears that this can be used to register the Time Capsule (or Mac) with .Mac. An anonymous Tim, commenting in the Apple support forums, suggests trying the following, with 'Foo' being your machine name and 'Bar' your .Mac account:

Hostname: Foo.Bar.members.mac.com

User: Foo.Bar.members.mac.com

Password: you get this by finding the Back to Mac entry in the system keyring, and copying the password from that.

On page 2 of 3: Disk Performance over the Network; Time Capsule Disk Formatting; RAID and Disk Spanning; Disk Performance; Disk vs Printer Sharing; and Upgrading or Expanding an Existing Network.

Disk Performance over the Network

Frank R. asks: "If my network goes down (or I just don't feel like using it) can I just plug my computer directly into Time Capsule to access my stored data?  if so, what is the improvement in transfer rate?"

Yes. The improvement is substantial, as noted below.

John Contarino asks: I am wondering if I can backup to Time Capsule through Ethernet? I could then use Time Capsule as my external hard drive for Time Machine as well as my wireless base station. Or would it be better / faster for me just to get an external Firewire drive and use that for Time Machine.

Yes. Over Gigabit Ethernet, backups and file access are dramatically faster than wireless, but not as fast as a directly connected Firewire drive.

Martijn B. from the Netherlands asks: "Provide specific attention to the Time Machine user interface when browsing through files and through time, which I find very jerky when using the USB hard disk connected to my Airport Extreme (after 'hacking' the system preferences). Big improvement however since the previous bug fix in Leopard, before which it didn't work at all."

Paul A. of Compuware volunteered an answer: "I suspect you will receive a flood of requests for comparisons of performance in accessing the Time Capsule internal hard drive versus the AirPort Extreme with an external USB 2.0 drive. In my experience with the AirDisk (i.e., AirPort Extreme and external Western Digital "Mybook" drive), I concluded that a significant limiting factor was network speed.

When first deployed, I had yet to upgrade my network architecture to Gigabit Ethernet. At that time, I noted the following behavior:

Copying large files to the AirDisk, I found performance not blazingly fast but acceptable.

Copying thousands of small files to the AirDisk, as would be typical during a backup, was painfully slow.

The shared 180GB iTunes library on the AirDisk was sluggish but usable.

The shared 10GB iPhoto library on the AirDisk was slow to the point of being unusable.

After a month, I upgraded my network architecture to fully support Gigabit Ethernet. I immediately noticed a huge increase in performance when accessing the AirDisk. Copying thousands of small files was still noticeably slower than copying larger files but quite acceptable. Using the shared iTunes library was only slightly slower than with a locally stored library. The shared iPhoto library was not as snappy as a local library but infinitely more usable than before.

While a bit long-winded, my overall point is that a proper test of the hard drive performance should attempt to remove the network architecture as a limiting factor. If the AirPort Extreme / TimeCapsule and connected computers are all using Gigabit Ethernet, you'll get a much better comparison of hard drive performance. You do this for a living, so you probably planned for this contingency already. ;-)

A second point is that a large iPhoto library is a good barometer of the comparative usability data on the network drives. If you have a hefty iPhoto library available, you might try this. The Event view in iPhoto is especially demanding as you scroll through thumbnails.

That provides a pretty good outline of what users can expect in terms of WiFi to share files and media libraries. We are still working on measuring benchmarks between wireless use, Gigabit Ethernet, and directly attached USB or Firewire drives.

Time Capsule Disk Formatting

Franco V. from Italy asks: "Option to reformat the internal disk with HFSX Case Sensitive?"

No, the AirPort Utility software has no provision for changing the disk format. However, the drive is being read and served up from the Time Capsule (or Extreme) itself, and presented as a shared volume. That means the unit's firmware would also need to be case sensitive savvy.

Joerg E. from Germany asks: "If you make Time Machine backups on a local USB drive, it creates a copy of the original files as a regular file system using hard links. On the other hand, if you make backups to a hard drive on another Mac in the local network, it creates a sparse image file, very similar to FileVault in Leopard. Myself, I feel much more comfortable with the regular file system, knowing I can always get direct access to the backed up files."

Yes, Time Machine always uses sparse image files to save backed up files to network volumes. This allows it to use hard links within the HFS+ disk image even when that image is saved on a foreign file system that does not support HFS+ features.

Joshua B. asks: "In your review of Time Capsule, would it be possible to remove the hard drive, replace it with a new one, and see what happens?"

The drive is erased and set up for use with the device, just as with plugging in a blank USB disk.

RAID and Disk Spanning

John N. of Minnesota asks: "Does is allow two (separate but identical) external hard drives that are configured to be RAID 1 to be attached and recognized? With the Extreme, the drives need to be in one enclosure acting as a single drive in order to be recognized."

Neither the Extreme nor Time Capsule does any RAID striping or mirroring on internal or attached drives. To use a RAID volume, it would need to be a self contained unit with a USB interface.

Tadd T. asks: "If I attach an external drive to a time capsule, will the Time Machine see the two drives as one backup device?  I ask this because my Mac Pro has 2GB of HD and I'd really like to find a backup target that is > 1GB so I can do a more complete backup.  Time Machine so far seems to not be able to span multiple volumes with its backup even if it is backing up multiple volumes from the client computer."

Neither the Extreme nor Time Capsule does any JBOD concatenation or disk spanning on internal or attached drives. To use a series of volumes acting as one large logical drive, it would need to be a self contained unit with a USB interface.

Disk Performance

Adam T. asks: "I was wondering if you could find some way of evaluating the actual hard drives.  This is apparently "server grade" but I have no idea what that means.  For example, am I better off getting a 1TB version, or connecting a 500GB drive to a 500GB model?  How would this stack up versus a G-Raid drive?  How about against a myBook drive, etc.?"

If you're planning to use Time Capsule or any other wireless server product, the speed of the drives and of the server will have no impact on throughput because the weakest link will be the wireless network. Any speed advantages would only be visible to computers attached directly to the wired LAN using Gigabit Ethernet. We are still doing performance testing to benchmark how great of a difference this makes, but it will be very similar to the performance of the AirPort Extreme.

Disk vs Printer Sharing

Theo K. asks: "I was wondering since the time capsule has only one USB connection which would requiring I guess a USB hub for additional connections. Can the review include testing of an attached USB printer to share and an external USB disk to backup to and see if they work alright at the same time, if printing is disabled while a backup is in process or does the backup pause while printing and then automatically resume where it left off."

We can test and update this later, but there should be no significant interruption of printing when using file sharing. Any use of the wireless network will be impacted by performing backup operations, but following the first full backup, Time Machine typically only has a small number of files to transfer in subsequent backup sessions.

Upgrading or Expanding an Existing Network

Bob B. in Ohio asks: "In your upcoming review of Time Capsule, it would be great if you could comment on the difficulty of using Time Capsule with an existing wireless router. I have a 2Wire DSL combination modem / wireless router, and I've read that it can be difficult adding another wireless router (Time Capsule) onto the LAN. Perhaps the trick is to disable the 2Wire wireless feature - I'm not sure. It almost appears, from the preliminary overview in Appleinsider, that Time Capsule handles this during the initial configuration. That would be awesome."

 

It is much easier with the new setup assistant to import the existing network setup from an existing base station to the new one, or to choose to add Time Capsule to an existing network to extend it rather than replace it. If you are using a DSL router, Time Capsule wouldn't replace the unit entirely but could either extend the existing network, providing faster 802.11n service, or replace the DSL router's wireless functions. There is still some complexity involved in setting this up. Extending the network would be the easiest option to follow.

Ted D. asks: "How do I setup the system so that I can replace an existing Airport base station, yet still use that station to extend the network to a different part of the house. That is, I want take my cable modem off the old Airport, put it on the Time Capsule, yet still be able to use the old Airport to extend the range of the network and be able to attach a network printer.

The easiest and ideal option is to extend your existing network with the Time Capsule, leaving any slow devices connected to your old base station and using the Time Capsule with 802.11n devices. An extended network shares the same DHCP server and address space, which prevents problems with seeing shared files and libraries on the local link network.

On page 3 of 3: Time Capsule with AirTunes, Xbox, Linux; Network Sharing; Power Consumption; Time Capsule as a Media Library Server; Mixed Wireless Network Performance; and Shared Disk Reliability Compared to AirPort Extreme.

Time Capsule with AirTunes, Xbox, Linux

Paul A. in New Zealand asks: "If you use an Airport Express for digital audio out to your stereo, how do you set up Time Machine to be compatible with it?  It can't replace that function can it?"

Time Capsule doesn't have audio outputs for AirTunes, but can be used on the same network with AirPort Express or Apple TV, both of which can act as speaker sources for streamed audio. Time Capsule (or an AirPort Extreme) would merely relay the wirelessly streamed audio to those other devices.

Steven F. asks: "Try and see if you can get a Xbox 360 to connect wirelessly using the Time Capsule as the wireless router.  I have not been able to do this... And it seems many others havent as well."

You might try putting the Time Capsule into the slower b/g only mode, as the Xbox 360's wireless option only supports 802.11g.

Martijn B. asks: "Accessing Time Capsule's hard drive as a Samba share from a non-Apple computer. I tried this with Airport Extreme, from a Linux client, but the connection gets dropped after a while. (I use this Linux device, a Freecom FSG, as my main storage, which I want to back up)."

We can do more testing of Samba (Windows File Sharing protocol). There are also reports of problems with users on Macs connecting reliably. Ideally, you should report any problems you have with as much information as possible so that Apple is aware of the problem and can resolve it.

Network Sharing

Finn in the UK asks: "Can it be used as a 'network storage' drive instead of a backup drive in a mixed PC and Mac environment. I would like to get one Time Machine to store all my Word, Excel, JPEG files, etc and have them available to both Win XP on a Dell, on an iMac in OSX, and on an iMac running XP under boot camp or Fusion. Possible? Can the different OS systems read/write to the file system?"


Yes on all counts.

"I’d then like another Time Capsule so that the first TC can backup to the second TC. I want to put the first TC in my study and the second in my detached garage so I have a remote backup. Possible?"

 

There is no provision to automatically mirror or copy files between units. This would require using a host computer to attach to one unit as a backup volume, and then back up its files to the other unit.

Backup Impact on Network

Josh B. asks: "I have an old iBook G4 that only supports .11g networking, so I'd like to know how long the initial backup takes (let's assume 40GB of data on the laptop HD for a good benchmark) and how long the incremental backups take. I'm also interested in how the wireless backups affect wireless network speeds for internet browsing, etc. Finally, I'd be interested to know if there's a noticeable difference when backing up and/or browsing during a backup whether you're using .11g or .11n networking. I'm considering an upgrade to a MBP in the near future, and would like to know if the .11n makes a big difference as far as Time Capsule is concerned. If you could find a way to include some or all of this info in your in-depth review I would sure appreciate it."

The previous 802.11g is significantly slower than 802.11n for local file copy operations. Browsing the web does not tax wireless networking, as your Internet connection is likely a fraction of the bandwidth of 802.11g. However, copying large amounts of files will certainly have an impact on other network activities. We will try to provide a more definite answer in our benchmarks.

Power Consumption

Nick L. asks: "Please could you take a detailed look at power consumption, and note whether or not the unit has a standby function? I note that there's a hard drive and a reasonably large fan, and I'd be hesitant to leave the unit on 24/7 unless both these power down automatically."

Simone R. asks: "One thing that I find disappointing of my AirPort Extreme is that it never puts to sleep the attached USB drive (well, at least the one I connected). I would like to know if Time Capsule puts the internal hard drive to sleep when not in use."

Neither the Time Capsule nor the AirPort Extreme power down drives, but the unit has a 30 watt power supply; it is not a large consumer of power. Server applications don't typically power down drives because doing so would cause a major stall in performance every time you used the drive, and would interrupt network operations.

Time Capsule as a Media Library Server

Andrew A. asks: "Apple TV / iTunes library server? Will it operate with more ease than the current airport disk option?"

Time Capsule operates nearly identically to AirPort Extreme's disk sharing.

Paul K. asks: "A common question no-doubt: Is it possible to use the Time Capsule internal drive or attached USB drives to store and share an iTunes library between multiple macs and Airport Expresses via AirTunes and/or iTunes sharing? The same question applies to iPhoto libraries."

Sharing an iTunes or iPhoto library between systems is possible, but multiple machines can't use the same library at once; one machine has to manage the database at a time. AirTunes on the Airport Express (and Apple TV) only act as relays for streamed media from iTunes.

David W. of Boston asks: "Do you know whether the Airport Express is going to be upgraded to ‘n’ for use with Time Machine; the Express is the only device (that I know of) that has audio-in, necessary for iTunes broadcast setup over wireless — I use that now with a b/g network (on an Extreme set to b/g), but I’d like to switch to the speed of ‘n’ for wireless backup, if I can keep the wireless iTunes."

It makes sense that AirPort Express would eventually migrate to using 802.11n as prices go down, but until that happens, Apple TV can serve as an AirTunes relay, and it supports 802.11n networking.

Terence J. of France asks: "Can I transfer all my movies/music to Time Capsule to free up space on my Mac and still have access to them wirelessly from the Mac or via an Apple TV connected directly to Time Capsule? - Basically can a Time Capsule/Apple TV combo act as a media Hub/server? Will the wireless transfer speeds be a problem?

You can transfer your iTunes library to a network volume, but Time Capsule does not act as a copy of iTunes itself, nor can the Apple TV stream from it directly. It can stream from your Mac or PC running iTunes with its media library located on a network drive.

Mixed Wireless Network Performance

William T. asks: "I believe Time Capsule, as a "dual-band" router should support simultaneous 802.11n and 802.11g networks. Can you please compare network performance with Time Capsule handling only an N, versus N and G networks simultaneously?"

Time Capsule only hosts one wireless network, even when supporting both 802.11n and 802.11b/g clients. The use of g clients on an n network does have an impact on the overall speed of other n clients, but only when the g clients are actually sending data. Slower clients can be attached to a slower base station on the same network to prevent this slowdown, allowing the n network to operate at full potential.

Shared Disk Reliability Compared to AirPort Extreme

Steve L. writes: "I'm one of those who expected to use my Airport Extreme + attached USB disc for Time Machine backups. I have had success doing just that by:

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

and then assigning the USB disc to Time Machine. Of course, a few weeks later I managed by some unknown means to trash the image, and even Disk Utility / Repair Disk failed to recover it. (Aside, I should have tried Disk Warrior, which I've found can often recover a volume that DU cannot.)

Attached is an image of the version numbers of Airport Utility and Airport Disk Utility here - I'm curious how they compare with what you have, in particular Time Capsule's firmware version. II am running an up-2-date 10.5.2."

Time Capsule ships with firmware version 7.3, compared to 7.2.1 for the AirPort Extreme. It also ships with AirPort Utility 5.3 (build 530.22) compared to 5.2.2 (522.3). Airport Disk Utility is the same version 1.2.1 (121.4).