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2 port link-agg for client computer
my prospective clients always ask me if 2 ethernet connections go twice as fast as one. of course the answer is no, but i thought of an instance where it might be faster, and i’m wondering if anyone has tried this. please remember i’m not a networking guru so if i’m totally wrong on this, be nice.
with link aggregation, as i understand it, you can only have one point to point connection between 2 computers no matter how many lines are in the link. with a 6 port card in the server, running through the switch with link-agg on, but only have one target (client) computer; then you only have one connection.
but i’m wondering, if you’re rendering a file in Final Cut, an instance where you are both reading a file from the server (one link) and writing a new file back to the server at the same time, would it create 2 links if its a 2 port link agg on the client? and if it does create 2 links, would it then go faster since one line would be used for read and one line for write?
in addition to that, what about rendering locally? if you create a simple RAID-0 with Disk Utility you can get very fast speeds with only a few cheap drives using the internal bays in the Mac Pro. if you have a project with render files on Edit 1, then move the project to Edit 2 (which still needs to access the render files on Edit 1) would a 2 port link agg on the clients speed up this occasional transfer?
thanks
e
Eric Hansen, The Audio Visual Plumber – http://www.avplumber.com
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1 Reply
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the answer, directly from God (you know who I mean Eric) –
Q: Can you trunk with link aggregation from the server to the client and go twice as fast?
A: No. This is a common misconception. Many inexperienced Apple resellers will make this mistake, which is why you want to talk to a networking expert before installing any serious infrastructure.Link aggregation works by load-balancing “sockets” (referred to in the IEEE 802.3ad spec as “conversations”) over all of the available ports. On a server, this works wonderfully since a server might have 10 clients connecting. Each of these 10 sockets can be routed over a different port, providing an evenly-loaded network with a higher aggregate bandwidth.
Clients generally connect to one server. Hence, if you run link aggregation on a client, this one socket (conversation) will run over one of the ports. You might see some traffic on the second port if you’re also checking e-mail or viewing web pages, but you won’t see 2X the bandwidth to the server. Some people implement link aggregation on clients, but it’s primarily for redundancy (fail-over capability).
FOR YOUR NEXT QUESTION – I will make up a silly answer –
“in addition to that, what about rendering locally? if you create a simple RAID-0 with Disk Utility you can get very fast speeds with only a few cheap drives using the internal bays in the Mac Pro. if you have a project with render files on Edit 1, then move the project to Edit 2 (which still needs to access the render files on Edit 1) would a 2 port link agg on the clients speed up this occasional transfer?”My silly answer – just following what others do – RENDER LOCALLY, then transfer your rendered files to the shared volume. If you want to bog down these cheapo SAN systems, render on the shared volume, and watch the trouble you get. The only way to avoid this is to
dedicate 2 ports, bonded together, and give this to “Mr. After Effects”, so he doesn’t bog down the entire SAN. I’ve done this (as per the advice of you know who), and it works.Bob Zelin
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