High performance LAN

[amacieli]

OK, so kinda similar to some questions on the board already, but I wanted to get a feel for what the overall solution would look like. Let's say you have a server holding a couple of teras of DVD-quality video in gig chunks or more, and you want to be able to serve up potentially two videos to various PCs on the LAN.

Server: 4 Gb RAM, several 750 Gb Seagates in Raid 0, gigabit ethernet port, FreeNAS.
Switch: D-Link 16 or 24 port gigabit switch
PC: MythTV or MCE, gigabit ethernet
LAN: large frames switched on

If you have two PCs trying to get video from the server at the same time, would the LAN be saturated? Would the server be fast enough or have enough RAM to cope? Would there be any "dropouts" in the video?

Bonus question: Is there a way of connecting two ethernet ports of the server and two of the PC to double the bandwidth?

Am I just being silly?

 

[SciFiMan]

How fast is the server CPU? Are the disks fast such as 10K or 15K? What OS is on the server? Windows Server 2000-2003? If the NIC's support it you can Team them for higher speed or redundancy. You can't on the PC side though (XP, etc.)

Are you using streaming software or just having the client double click the video file in a shared folder?

 

[thepustule]

And how much video will you lose if one of those 750G drives dies? They do that quite often you know...

Even full DVD-quality video doesn't really take up all that much bandwidth on a LAN...

 

[nh484000]

Yeah i think my question was about the same subject. I'v asked a few people around school (I go to school at UNH) and noone seems to know. I wasnt planning on running a full serve but i do have a pc that if quite fast that will be hosting the media.

 

[thepustule]

As a rough indication anyway, here are some general numbers. I got all of these from mplayer. It spews some interesting info before the video starts playing, which can help with requirements like this:

Raw DVD-quality Mpeg2 compressed movie - 8megabit
DivX Mpeg4 compressed movie of reasonable quality - 1.8megabit
H.264 compressed movie (from DVD source - not HD) - 1 megabit

Bear in mind that all of the above are 480p video, which I have compressed using the 3 different methods above, to a level which I feel still gives me a DVD-like viewing experience. HD video, of course, would require much more bandwidth. Your Mileage May Vary.

 

[lotussama]

A common 100baseT network would suit your needs just fine, I would say. Like you said, at uncompressed DVD rates, you're using 8mb/s, whereas a 100baseT network will likely offer you around 90mb/s. If you want to futureproof it, step up to gigE, but you may need to buy a new switch and such.

Also, bear in mind that any speed bottleneck is going to be your network...I'd get those drives on the server off of RAID 0 ASAP. Perhaps RAID 5 for redundancy. The point is, when you know your network is going to be your bottleneck, hard drive performance really doesn't matter, so go with something a bit more fault-tolerant than a striped set.

 

[thepustule]

Hmmmm

I'm not so sure the network will be the bottleneck. If a video stream uses 8megabit and a 100meg network is capable of 90megabit, how is the network the bottleneck?

Having tested several systems on gigabit networks, it seems that only the VERY latest systems with PCI-E Network cards can actually manage to sustain a solid 900megabits of traffic, and even then only if they are stripped down and don't have very much running on them.

No, I'm afraid we're past the good old days when the network was the bottleneck.