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Discussion Starter · #1 ·
I was planning to build a very simple media server for all my music, movies, etc. and I recently started considering the option of reusing an old computer instead. Really all I need out of the new machine is a GigE connection and a SATA RAID (planning on 6-channel, RAID 5). I also want the power consumption to be as low as possible for 24-hour operation, which is another plus to reusing an old machine.


I was considering using an old Athlon 700 I have here, which means I'd need a GigE PCI adapter, as well as the RAID controller, and most likely a beefier power supply. My biggest concern is the limited PCI bandwidth, especially with data having to traverse the bus twice to get from a disk to the network. Also the RAID card would already be limited by the 32bit/33MHz, since most cards are designed for 64bit and higher speeds.


I was looking for some comments on how badly this would slow things down. Would it be worth it to buy something like a new Celeron and mobo with built in GigE instead? Worth it to get a mobo with 64bit PCI or PCI-X? I'm not concerned about getting the absolute fastest speed possible, I just don't want the slower PCI bus to bottleneck the system. As long as I can get data out the GigE port as fast as the harddrives can read it I'll be happy.


Thanks in advance for your suggestions.
 

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You will completely saturate the bus no doubt about it.

PCI only has about 120MB/s, which is about the max throughput for GIGe, much less a solid raid5 setup that can push 180MB/s


Getting an intel setup with integrated GiGe or the new Nforce 3/4 with GiGe, that will take all the load off the PCI bus.


I have a server at work that I recently built with a 7 disc SATA raid 5 setup with the highpoint rocketraid and it sustains around 180MB/s, which is well above the PCI limit, it's running 64bit/133mhz PCI-X


So if you have a 6 disc array and aren't on a 64bit PCI or PCI-X it will bottleneck your xfer rates, but you'd probably average aroung 150MB/s, but instead would be limited to about 120MB/s
 

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Discussion Starter · #4 ·
I'm sorry I should have been more clear as Stanger makes a good point. The main intent of this server is to stream movies and/or music to an HTPC in another room. In some rare cases there might be another computer in the house also streaming a file from the server, say if one room is listening to music and the HTPC is watching a movie.


The server will have absolutely no other function, no web serving, email, etc. so as long as it can stream 2 .vob files (total worst case) out the GigE port it should be fine. With this in mind is the saturation of the PCI bus still a big problem?
 

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The 700 cpu and 33 mhz pci bus will be the 2 main chokers.


Maybe consider something like a Tyan 2460 with a single cpu? It'll handle regular non-MP Athlon XP's (single and dual) and non-ecc memory if you want to use them. I get about 80MB/s using gigE and 30-40 using a 33 bus board with the same ethernet card.

http://www.tyan.com/products/html/tigermp.html

http://forums.2cpu.com/
 

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Discussion Starter · #6 ·
That Tyan solution looks pretty nice, they even have a board with built in GigE. I couldn't determine if it's through the north or south bridge, but either way it would save me from buying a PCI adapter. Unfortunately mine is one of the first Athlons, with the Slot A, lol. This means that buying a new mobo necessitates buying a new processor, which means I may as well spend a few extra bucks on the project.


If I just reuse the crappy Athlon and mobo I have now do you think I'll be able to stream 2 .vob files at once to other computers? I figure if you take the PCI bandwidth, 133MB/s. Divide by 2 for the 2 streams, and 2 again because the RAID and GigE are sharing the bus, you get around 33MB/s. Obviously there's going to be overhead involved, so maybe 20MB/s output for each stream is still possible? This should be enough for my purposes, but with such a loaded PCI bus and such a slow processor I'm afraid it will still cause frames to be dropped in the video.


So in the end is it worth just buying a new system? And if so would you recommend Celeron or Athlon/Sempron if low power was the primary concern?
 

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Quote:
Originally posted by Magius
I'm sorry I should have been more clear as Stanger makes a good point. The main intent of this server is to stream movies and/or music to an HTPC in another room. In some rare cases there might be another computer in the house also streaming a file from the server, say if one room is listening to music and the HTPC is watching a movie.


The server will have absolutely no other function, no web serving, email, etc. so as long as it can stream 2 .vob files (total worst case) out the GigE port it should be fine. With this in mind is the saturation of the PCI bus still a big problem?
If this is your intended usage, performance is not a concern at all. In fact, Gig-E and RAID are overkill, as their performance is orders of magnitude higer than would be needed to stream a few VOBs.


For quite a long time I used a 450MHz Mac G4 Cube as my media server (with a couple large drives hanging off it via firewire). I used it to store DVD movies, iTunes Music, and HDTV captures. The HDTV captures are over twice the bit rate of DVD movies, and even with that old G4 it could easily keep up with three HDTV streams.


The only time I ever noticed any performance limit was when doing bulk xfers (backing up all my data to upgrade one of my hard drives). In this case, the 100Mbps ethernet port on my G4 Cube was the bottleneck.
 

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Discussion Starter · #9 ·
Thank you tji, that is exactly the response I was hoping for. For what it's worth the GigE is primarily for future headroom, and since all my other computers are running it, it made no sense to have the server running 10/100.


Also as I said previously the RAID configuration is not for any performance benefit, I'm not concerned with eeking out the last bit of speed. The reason I'm doing RAID is for the little bit of redundancy it will provide. Since I'll be backing up DVDs and CDs and will always have the master copy I don't need a super redundant array, I just want some measure of protection for all the time I'll invest in backing them up.


I'm glad you posted about your personal experience becase now it's definately worth investing $30 in a GigE PCI card to make use of the machine I have before spending lots more building a new system. If I wind up disappointed in the performance later I can always look for a PCI-X motherboard and I'm only out the $30. Thanks again to everyone who posted.
 
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