Wikipedia:Reference desk/Archives/Computing/2015 February 18

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February 18

Connecting External HDD via Wi-Fi

I have recently bought an external HDD for my Macbook Pro, and would like to know if there are any options for connecting it wirelessly, as I am covered in cables from various other devices. KägeTorä - (^影_虎) (Chin Wag) 17:48, 18 February 2015 (UTC)

Sounds like a really bad idea to me. That's a lot of data to send via WiFi, slowing things down dramatically, and then there's the security risk. For excess cables, I suggest using wire ties to tie up the excess and tie the wires into manageable bundles.

Perhaps some other wired devices could go wireless, instead ? What devices are presently wired to your laptop ? StuRat (talk) 17:58, 18 February 2015 (UTC)

You need something like a Network Attached Storage device that takes you drive (is is USB, eSATA, Apple lightning/thunderbolt?. The NAS converter will either be WiFi, or ethernet. If it's ethernet, connect it to your WiFi router. However, as others have pointed out, WiFi is rated at 58MB/s,modern hard drives can support 200 MB/sec. LongHairedFop (talk) 13:08, 19 February 2015 (UTC)

There are many different small file server appliances (and some wireless gateways which have this functionality built in). Hard disk makers like Seagate and Western Digital make them (or disk enclosures with WiFi built in), as do home networking companies like Belkin and Netgear. Or you can build your own with a cheap single-board computer like a Raspberry Pi running FreeNAS. Search your favourite computer-stuff retailer for terms like "home NAS" or "home cloud storage". -- Finlay McWalterᚠTalk 18:00, 18 February 2015 (UTC)

I have a Macbook Pro, external HD (portable, USB bus powered) and Apple Airport Extreme 5th Gen. Networking the HD is painfully slow - far too slow to be useable. A powered USB hub should have speeded it up, but didn't: probably because my powered USB hub only has a 5v power supply whereas the HD motor is 12v. Certainly it can do Network Attached Storage; the 6th Gen router can also do Time Machine backups via wifi.80.111.95.153 (talk) 18:33, 18 February 2015 (UTC)

If the HD didn't have enough power it almost definitely simply wouldn't work (or would only work intermitedly) so the powered hub isn't really useful. Anyway there are several reasons why networking the HD may be slow in your case, it's difficult to say why without more info. As mentioned above, wifi often isn't that fast. Notably while 802.11ac may theoreticly be able to do 1,300 Mbit/s (or more) your chances of achieving this are slim. (Well probably zero, I don't know if anyone has ever done so in real world conditions.) You will need to be using 5ghz and very close to the access point and using multiple channels etc. I don't think it's that uncommon that even being in the next room may limit your speeds to a few MB/s. Also HDs are resonably fast, but USB2 is slow. If either the HD or the host device (e.g. NAS) only has a USB2 port, then you shouldn't expect more than 25-35 MB/s (that's the maximum speed you'll get even if the HD is connected directly). The 5th gen Airport Extreme only has USB 2.0 [1]. Of course even 25-35 MB/s could be unrealistic. Some routers with NAS are very poor performers and can't even achieve that whether because the USB chipset is crap, or more likely because the CPU is simply too slow. The Airport Extreme is supposed to be decent, so I would hope the 5th gen would achieve at least 25MB/s on a wired connection, but I have no real idea. Nil Einne (talk) 18:05, 19 February 2015 (UTC)February 2015 (UTC)

Some further research found some interesting things. For example [2] shows USB3 performance on that router is shit (note this is with a wired connection [3]). With some of the other router examples, I'm not sure whether it's USB2.0 or USB3.0, but performance is very poor even for USB2.0. This demonstrates what I was talking about above.

This [4] is far better, in fact you're probably going to hit the limits of GbE soon (e.g. although fairly old [5] only achieve 111 MB/s).

I think, but I'm not sure there is a mistake in this [6] chart, as the speed numbers for USB3.0 are very similar to what they got from the wired performance, but the wired storage performance is in MB/s (which is what I'm pretty sure it should be), but the wireless implies it's Mbit/s. The general wireless performance suggests it should be able to achieve those MB/s even on wireless (particularly in light of the comments which say wireless uses a different CPU, so shouldn't affect storage). And the USB2.0 speeds also match with what you would expect from USB2.0 in MB/s.

Also, [7] may be of interest. With the worst router, you can perhaps achieve about 120 Mbit/s for 5ghz or 100 Mbit/s for 2.4ghz. This isn't quite a few MB/s, but still isn't that great, and these are fairly recent ac devices. As can be seen from [8] and [9], 21 dB could be something you would expect upstairs in the next room, or in two rooms over [10]. So not quite the next room, but not that much further. (Plus I'm pretty sure that means with a high quality transceiver on the host end, since the intention was to test the performance of the router.)

Perhaps most interesting is [11]. I guess some here knew this already, but I I'd never heard this before. It seems in certain circumstances USB3 can affect 2.4ghz devices in a significant way.

I think the take away message from this is that you can achieve decent speeds with even a router's built in NAS on wifi, but your speeds will probably be slower than the HD attached directly, presuming it's USB3 (or eSATA or Thunderbolt). And it will depend a lot on the router, as well as distance etc. The other alternative is to make a standalone NAS, whether with a wifi connection (which will probably limit speeds since it's likely you'll be going from the NAS to the router to the computer), or a wired connection to the router. Of course your router still matters in either case since if it can only achieve 100 Mbit/s even when you're right next to it, you're never going to get better with your NAS.

Nil Einne (talk) 19:25, 19 February 2015 (UTC)