Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

ShadowExt

macrumors newbie
Original poster
Jan 3, 2014
2
0
Canada
Is it possible to bridge the two Gigabit ethernet ports on the 2013 Mac Pro to double the throughput? (Link aggregation)
 
Oh, hell yeah!

I've got link aggregation going on my 2006 Mac Pro 1,1. There is no doubt the new Mac Pro will do it.
 
I've seen conflicting reports over whether link aggregation actually allows for double the bandwidth with protocols that don't explicitly support it. Are folks actually getting more than 1000 Mbps (~125 MB/s) over aggregated gigabit ports via, say, built-in file sharing on individual file transfers?
 
I've seen conflicting reports over whether link aggregation actually allows for double the bandwidth with protocols that don't explicitly support it. Are folks actually getting more than 1000 Mbps (~125 MB/s) over aggregated gigabit ports via, say, built-in file sharing on individual file transfers?
While I haven't tried it, I can't see why not. File sharing (AFP/SMB) and other Layer 7 protocols shouldn't have to know anything about Ethernet link aggregation to take advantage of it. In fact, they probably don't even know it's going on.

The only issue I can think of that wouldn't allow of the doubling of speed is if the two Ethernet ports are on the same PCI bus, and perhaps the saturation point is between 1000 and 2000 mbps. However, the Mac Pro (the new one, anyway) has the ports on separate buses, eliminating this problem.
 
I use Link Aggregation with my 2009 Mac Pro, and the Cisco 300 series hubs which aren't expensive, but run the enterprise iOS. Works great now. It used to be really flaky about establishing a connection, but it was (YET ANOTHER) OS X bug that got fixed in the last year.

Whether it's doubling the bandwidth or using failover isn't clear and I haven't done tests. My impression is that the link aggregation protocol allows for either failover or throughput aggregation. In my Synology 1211+ which is set up with the same feature, it has LED lights and clearly looks like it's using failover (packets alternate on either line). I don't know what is done with the Intel chips in the Mac Pro under OS X or Windows (where you can download Intel drivers to enable it too).

Anyhow I'll be setting it up on my nMP for sure. Those ports have direct and individual PCIe lanes to the CPU so latency should be quite low. Oh, I also use Jumbo frame (9000 MTU) on my LAN.
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
I use Link Aggregation with my 2009 Mac Pro, and the Cisco 300 series hubs which aren't expensive, but run the enterprise iOS. Works great now. It used to be really flaky about establishing a connection, but it was (YET ANOTHER) OS X bug that got fixed in the last year.

Thank you for sharing. My QNAP NAS has dual gigabit Ether and nMP has also, so I am tempted into buying a Cisco 300 series hub.
 
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
Thank you for sharing. My QNAP NAS has dual gigabit Ether and nMP has also, so I am tempted into buying a Cisco 300 series hub.

They're quite good. Make sure you update to the latest firmware. They just released a version that changes the internal filesystem, so make sure to read the instructions on how to do it. You have to update both the boot loader (over SSH) and the firmware. Note that the boot loader SSH (SCP upload) isn't compatible with OS X, you have to have a Linux box or virtualized to load from. The new version is more feature rich and faster than previous.

The other thing is that iOS has a million features and takes some doing to understand. You'll have to reboot your switch several times (after setting L3, and again after Jumbo frames), and make sure you have a computer with a serial port in case you lock yourself out of the switch!

I use the VLAN technology extensively too.
 
With LACP you only get the speed of a SINGLE link between two IP's.

So Mac Pro <-> NAS is only ever 1Gbit even with dual 1Gbit connection in between.

If you're talking to 2x NAS, or a NAS talking to 2x hosts, then you can see 2Gbit in aggregate traffic.
 
With LACP you only get the speed of a SINGLE link between two IP's.

So Mac Pro <-> NAS is only ever 1Gbit even with dual 1Gbit connection in between.

If you're talking to 2x NAS, or a NAS talking to 2x hosts, then you can see 2Gbit in aggregate traffic.

Not sure what you're saying here. I have 802.3ad enabled, which I believe is either aggregation or failover. LACP can be enabled or disabled, and is simply a communication protocol for the nodes to negotiate the aggregation, AFAIK.
 
Not sure what you're saying here. I have 802.3ad enabled, which I believe is either aggregation or failover. LACP can be enabled or disabled, and is simply a communication protocol for the nodes to negotiate the aggregation, AFAIK.

For a transfer the max speed is 1 gbit/s. The nas server can pump out 1 gb/s to machine 1, 1 gb/s to machine 2, etc. for how many 1 gb/s links it has aggregated. But, each client machine gets 1 gb/s. The nmp can talk to 2 different machines, each at 1gb/s, so at an aggregated 2 gb/s total.

Yeah, when do they put 10 gb/s ethernet into mac pros? Server boards have 10 gb/s ethernet. You can buy a pcie card for the old mac pros, but not the new. I hope in a few years they use 10 gb/s ethernet built in.
 
With LACP you only get the speed of a SINGLE link between two IP's.

So Mac Pro <-> NAS is only ever 1Gbit even with dual 1Gbit connection in between.

If you're talking to 2x NAS, or a NAS talking to 2x hosts, then you can see 2Gbit in aggregate traffic.

My TS-439 has two gigabit ports. I expect that MacPro and the NAS will be linked at 2GBit/sec by Load Balancing.
 

Attachments

  • ScreenShot 2014-01-06 7.22.56.png
    ScreenShot 2014-01-06 7.22.56.png
    372.9 KB · Views: 307
For a transfer the max speed is 1 gbit/s. The nas server can pump out 1 gb/s to machine 1, 1 gb/s to machine 2, etc. for how many 1 gb/s links it has aggregated. But, each client machine gets 1 gb/s. The nmp can talk to 2 different machines, each at 1gb/s, so at an aggregated 2 gb/s total.

This makes no sense to me. The Synology NAS can pump out as much data as it can pull off the drives, aggregated to 2 Gbps. That's what 802.3ad means and the device has explicit support for it.


Yeah, when do they put 10 gb/s ethernet into mac pros? Server boards have 10 gb/s ethernet. You can buy a pcie card for the old mac pros, but not the new. I hope in a few years they use 10 gb/s ethernet built in.

Promise sells a SAN link for TB 2.0, up to 4Gbps. You can to 10 gbps ethernet over a PCIe card in one of the many external cages.
 
Not sure what you're saying here.

Just that despite having a 2x 1Gbit connection end-to-end (nNM, switch, NAS) you only get the speed of 1x link (1Gbit) for transfers between a single host and single NAS.

----------

This makes no sense to me. The Synology NAS can pump out as much data as it can pull off the drives, aggregated to 2 Gbps. That's what 802.3ad means and the device has explicit support for it.

It can send 1Gbit worth of data to each of 2 DIFFERENT hosts, so yes in AGGREGATE it's sending 2Gbit of data.

But only 1Gbit (link) max to each host.
 
Just that despite having a 2x 1Gbit connection end-to-end (nNM, switch, NAS) you only get the speed of 1x link (1Gbit) for transfers between a single host and single NAS.

----------



It can send 1Gbit worth of data to each of 2 DIFFERENT hosts, so yes in AGGREGATE it's sending 2Gbit of data.

But only 1Gbit (link) max to each host.

Maybe we're arguing the wrong point. Of course a 1Gbps client will only receive 1Gbps when talking to a 2Gbps host. However, per OP, I'm discussing a 2 Gbps MP talking to a 2Gbps NAS. Obviously the communication should be 2Gbps. In practice while I haven't measured I think my Synology isn't giving me that.
 
I encounter this somewhat frequently, which is what prompted me to reply.

People assume if they have 2x 1Gbit connections to the switch, and the NAS has 2x 1Gbit connections to the switch, that they can get a 2Gbit connection from the host to the NAS.

It doesn't work that way!

You only get a single link connection from point A to point B. In this case 1Gbit.

You can have 1Gbit from A to B, and another 1Gbit from A to C, so you're moving 2Gbit of data in aggregate, but you never get 2Gbit from A to B.
 
I think, switching hubs which support Link Aggregation (LACP) are expensive. I actually once tried to find such a hub. All of them target at enterprise users.

http://en.wikipedia.org/wiki/Link_aggregation

I use Link Aggregation with my 2009 Mac Pro, and the Cisco 300 series hubs which aren't expensive, but run the enterprise iOS. Works great now. It used to be really flaky about establishing a connection, but it was (YET ANOTHER) OS X bug that got fixed in the last year.

Whether it's doubling the bandwidth or using failover isn't clear and I haven't done tests. My impression is that the link aggregation protocol allows for either failover or throughput aggregation. In my Synology 1211+ which is set up with the same feature, it has LED lights and clearly looks like it's using failover (packets alternate on either line). I don't know what is done with the Intel chips in the Mac Pro under OS X or Windows (where you can download Intel drivers to enable it too).

Anyhow I'll be setting it up on my nMP for sure. Those ports have direct and individual PCIe lanes to the CPU so latency should be quite low. Oh, I also use Jumbo frame (9000 MTU) on my LAN.

Thank you for sharing. My QNAP NAS has dual gigabit Ether and nMP has also, so I am tempted into buying a Cisco 300 series hub.

A hub is not a switch and a switch is not a hub. You would use a hub or a switch.

FWIW - the Cisco small business series (S F/G 200/300/500X) does not actually run iOS but does through telnet or SSH support a small subset of the iOS commands.

I can confirm that that is the case.

People assume if they have 2x 1Gbit connections to the switch, and the NAS has 2x 1Gbit connections to the switch, that they can get a 2Gbit connection from the host to the NAS.

It doesn't work that way!

You only get a single link connection from point A to point B. In this case 1Gbit.

You can have 1Gbit from A to B, and another 1Gbit from A to C, so you're moving 2Gbit of data in aggregate, but you never get 2Gbit from A to B.

Quoted for truth


There is a lot of misinformation in this thread.
 
Last edited:
As an Amazon Associate, MacRumors earns a commission from qualifying purchases made through links in this post.
People assume if they have 2x 1Gbit connections to the switch, and the NAS has 2x 1Gbit connections to the switch, that they can get a 2Gbit connection from the host to the NAS.

It doesn't work that way!

I was one of those people who assume that.
Thank you for teaching. This was a good learning for me.
 
Interesting read http://www.ieee802.org/3/hssg/public/apr07/frazier_01_0407.pdf

----------

I wonder if someone could explain the reason(s) why there's a difference in the throughput of the 1513+ between PC only link and link aggregation. Aren't both use only 1gbps link?

http://www.synology.com/en-us/products/performance/#five_to_twelve_bay

Also, is it possible to increase the bandwidth by doing this:

Device A ............................Device B
Gb port 1 |-------------> Gb port 1
(LAG) ------
Gb port 2 |-------------> Gb port 2

Thanks in advance
 
Last edited:
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.