6- to 12-port switch recommendations?

A Former User

In the coming weeks, I have to image a bunch of computers that are isolated from my on-campus network. These computers are also on a wireless network on their own.

I’ve got FOG on a portable computer, so I’m going to take the FOG server to these computers, along with a switch and network cables.

Because the computers are in bundles of 6, I plan on imaging them 6 at a time using unicast.

Does anyone have recommendations for a small but fast switch? Doesn’t need need power-over-ethernet, and doesn’t need to be managed because we will be using it just for imaging. All the computers involved have gigabit ethernet.

I just want to be able to reliably image 6 devices at a time. I know the portable FOG server is not a bottleneck.

Wayne Workman

6 + the fog server, you need 7 ports minimum. I’d recommend none other than Cisco. And here’s a nice 8 port model: SG100D-08-NA Amazon and Newegg carries it. You might find one on ebay.

A Former User

Sorry, I should’ve been more clear: it’s 6 including the FOG server. I re-read my post and see I wasn’t clear on that.

That switch is only $50 – that’s rad. Have you used that one? That just seems cheap – not that I’m complaining as long as it gets the job done quickly and can handle the traffic.

Wayne Workman

@wayne-workman Yes, with fog too. It does fine for an un-managed switch. Also - Cisco is not cheap. This is just a very small unmanaged switch. There are cheaper ones available but they are less quality. Look I’m no salesman I don’t care what switch you buy.

I don’t know how much you know about networking or network devices but I’m going to educate you anyways. You should realize the model I recommended is nothing more than a switch. No wifi, no routing, no vlans, no dns, no dhcp, no no no. Just a switch. This is a small-business grade device that performs a single function. 50 dollars is actually high for an unmanaged switch - crap ones made by other companies go for much less. Like these for example:

So as you can see, 50 bucks is quite high, not cheap.
Also, with all this said - it is what it is. A low-end small-business grade un-managed switch. It will not perform like a 3,100 dollar Cisco Catalyst switch.

george1421

I’m going to take a different approach on this because the 6-8 port switch isn’t going to be your problem (well unless you pick a real crappy cheap switch).

Considering a consumer desktop/workstation as a fog server:
In my testing with a single spindle (rotating) hard drive had about 70MB/s transfer rates. So assuming everything is linear, at the 6 simultaneous unicast streams that gives you about 12MB/s or about 700MB/min transfer rate. So if you have a 15GB reference image it should take about 21 minutes to push that image to the target computer. Understand those are ideal times since disk seek times are not included in the calculations. Consider you would be pushing 6 image streams probably at different points in the image. That single hard drive will be bouncing all around to serve up the image.
Upgrading from a spinning hard drive to a SSD in the fog server takes you from about 70MB/s to 450MB/s. Two SSDs in a raid-0 configuration will net you about 720MB/s throughput.

You will reach max capacity on a single GbE network between 2 and 3 simultaneous unicast streams. This is because of link saturation. Yes you can image beyond 3 streams, but what will happen is you will start to see your retransmit count jump up dramatically. Setting up another NIC configured in a team or bonded connection will get you closer to the 6 unicast streams without too much packet loss.

Understand these are extreme testing without any overhead fog or the target computer may induce. The testing was done to see what the capabilities of the hardware and the linux operating system could manage.

Ref: https://forums.fogproject.org/topic/10459/can-you-make-fog-imaging-go-fast

The point of all of this is, maybe if you need to image 6 systems at the same time at a reasonable pace, you might want to consider a multicast stream. This method send out only one image, so you don’t need a fast disk subsystem or a huge network infrastructure. The downside to a multicast stream is the stream flows at the rate of the slowest computer in the multicast group. So if you are imaging 4 4-core desktops and an old 1-core desktop the transfer rate will be set at how fast the 1-core desktop can consume the data. The others will only ingest data at the rate of the 1-core.

Wayne Workman

@george1421 said in 6- to 12-port switch recommendations?:

you might want to consider a multicast stream

George is right. I had this in the back of my mind, but just wanted to address the switch question. Multicast should be used here no matter what switch you buy.

6- to 12-port switch recommendations?

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