How do I get non-Time-Capsule networked back-up working?
March 9, 2014 2:40 PM   Subscribe

I need to back up three Macs and an external iTunes library and want to do it via a drive attached to my router. My brain doesn't understand networking. I think I have all the required parts of the puzzle, but I'm clearly not understanding something important.

Here's the set-up:

1 x iMac with my iTunes library on an external drive attached to it via a cable.
2 x MacBooks
1 x ISP-supplied modem connected to the internet
1 x ASUS RT-N66U Dual-Band Wireless-N900 Gigabit Router connected to the modem and is successfully connected to the internet
1 x WD My Book Studio 2TB Mac External Hard Drive Storage USB 3.0 drive that's connected to the router but is seemingly invisible.

I had a look at this how to use a network drive with Time Machine, but can't see the My Book drive. I tried looking for other tutorials but not nothing of any use. I'm really hoping that I don't have to have that or the router connected to the iMac as we're incredibly short of space. How do I make this work?
posted by TheDonF to Computers & Internet (6 answers total) 1 user marked this as a favorite
It has been a few years since I tried doing networked backups with Time Machine. Perhaps things have been fixed, but my advice is: don't. Especially with the MacBooks, which have a tendency to have lids shut while the machine is carted off elsewhere, or hit Wi-Fi interference temporarily dropping connection.

At my lab, we used to have a weekly 1% failure rate for laptop -- networked -- Time Machine backups. Which does not entirely sound bad if the failure just involved a single backup session not completing successfully. But these failures are worse: if connectivity to the backup volume is interrupted in the middle of a backup, then the entire backup volume is corrupted (the sparsebundle in the video tutorial). You can no longer read from it, you cannot easily retrieve backed-up data, you cannot backup new data. To get it back, you would need to attempt a disk repair on the virtual disk on the external hard drive, and that would not always succeed. It sucks.

My recommendation would be to keep the drive plugged into a USB hub connected to the iMac, and periodically unmount and plug into the MacBooks and kick off a backup. It requires a bit more diligence, but it also means you will be at much lower risk of accidentally destroying your backups.

If you really want to do the networked backups, you need to configure the router to share the USB disk. By default the RT-N66U will not share the disk (which is why it does not show up in the Finder). I believe the RT-N66U does not have support for the Mac-default HFS+ filesystem, so the disk will need to be reformatted to a supported filesystem (ext3 seems to be online consensus from quick search).
posted by jraenar at 3:27 PM on March 9, 2014

Whoa, some confusion here. I have tested this extensively in a number of different ways.

Firstly, backing up to a network drive that isn't being served by either 1) a Time Machine device, 2) an AirPort Express, or 3) an OS X Server running Time Machine Service, is a use case that is not supported by Apple. In fact, it requires enabling an undocumented option in the client OS X.

If you insist on doing it, the underlying OS of the disk doesn't matter. CIFS/SMB, AFP, and NFS make all underlying file systems look the same to the client. And none of them expose the features of HFS+ that Time Machine uses when directly connected to a disk. Apple's effective workaround is to use an expandable sparsebundle on the remote disk, and store a whole, separate HFS+ volume inside that sparsebundle. This means that, yes, making operations clean can be tricky.

In my experience, the very biggest factor is the quality of the network file server. I run a household of multiple wirelessly-connected TM clients on an OS X Server host and my experiences have been flawless. Prior attempts at doing the same (including a Linux file host speaking Netatalk over an HFS+ volume, amongst others) were variously more or less stable.
posted by TheNewWazoo at 3:49 PM on March 9, 2014

If you are backing up over a network connection, let me add another voice to jraenar's saying do not do it with Time Machine.
posted by dmd at 4:32 PM on March 9, 2014

I'll play devils advocate and say do it. I have two separate drives connected via FireWire to an old PPC Mac Mini. Both my Macbook Pro and my wife's MacBook have been using the larger of these disks as a Time Machine backup for years now. The second smaller drive I use for manual backups (not incremental as in Time Machine) using Chronosync. Even the Mini uses the large disk for backup via Time Machine.

The key here is that the drive is hosted by the Mini, not the router (I have an Asus RT-N16, so could plug it into the router, but I would rather use FireWire than USB2). The second thing is that I have both laptops set not to back up unless they are connected to a power cable. This was initially done to keep my laptop from draining to zero battery as it's fairly old, but it has worked for us. I plug it in to charge overnight at least two or three times a week at home, and it backs up when I do so. I have never had a problem with it flaking out because I disconnected it from the network during a backup. (I do tend to plug it directly in to Ethernet at home though, because why wouldn't I want to use gigabit connectivity for this kind of thing?)
posted by caution live frogs at 10:29 PM on March 9, 2014

PS the drives I use are both HFS+ formatted, given that they are only used with Macs. The smaller drive actually came out of an old MyBook that died - I disassembled it and found that the drive was good but the controller in the case was shot, so I plopped it into a new external case.
posted by caution live frogs at 10:31 PM on March 9, 2014

Okay, this is what I did:

I gave up wanting to use Time Machine. It's never been reliable over wifi and I've had corrupted backups numerous times over the past few years. I didn't bother buying a Time Capsule as I had one of those and it died after 16 months, and Apple isn't getting more of my money for something that shoddy. Instead I kept my WD backup drive, bought a copy of SuperDuper! and have now instigated a Friday Night Is Backup Night policy (once per week is enough for the household). Super Duper's Smart Update option makes backups really quick and I use a USB cable to connect each machine to its own partition on the WD Drive.
posted by TheDonF at 11:48 PM on March 30, 2014

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