Work server for max tcp connections

[Jimmah]

At work we have 6 old-as-balls pc's running Ubuntu, sending simulated security panel heartbeats to our reciever for testing. Currently we're getting about 4000-ish connections using 3 old Sempron 3000+ AM2 cpu, 1gb ddr2 and 80gb hdd's and 3 P4 3.2, 1gb ddr, 40gb desktops (not our idea, they just showed up one day). We moved their lab with 3 racks holding all this crap a few weeks ago, the new space has enough room for 1 rack and it's full.

I've been given the wonderful job of scavenging parts from the old boxes to build one server to handle 5000+ tcp connections. My budget is 100$, and they would like it up within 2 weeks. I have a few good AM2+ boards, 4x 1gb ddr2 667, 4x 80gb SATA, few decent 2U and desktop cases, PCI and PCIe network cards, a brand new Antec psu and whatever OS I want as long as it's Linux.

Ideas I have are a. buy a x4 6** and hope for the best and b. ask for a bigger budget (not gonna happen), and c. sell it all and try to get enough to pay for new server.

Help.....

 

[mfenn]

What are to limited by when you pump the TCP connections up? CPU or memory?

 

[VirtualLarry]

Good luck. I have no idea what the CPU requirements are of your application, but an X4 isn't a bad idea.

 

[Jimmah]

What are to limited by when you pump the TCP connections up? CPU or memory?

A bit of both I believe. The cpu hits 100% or close to it and ram is at about 95% full. I will try overclocking one tomorrow to see how it does.

 

[Zap]

A bit of both I believe. The cpu hits 100% or close to it and ram is at about 95% full. I will try overclocking one tomorrow to see how it does.

Also try combining RAM from two machines into one. Do those separately from the overclock as well as combined, to see what the impacts are. It may be an issue of dropping in some cheap CPU and/or RAM upgrades.

 

[yinan]

Just virtualize the existing boxes into virtual machines on a scavenged parts ESXi host. That would probably be your easiest route.

 

[mfenn]

Also try combining RAM from two machines into one. Do those separately from the overclock as well as combined, to see what the impacts are. It may be an issue of dropping in some cheap CPU and/or RAM upgrades.

:thumbsup: To this. Also, you should determine how big your working set is. A lot of that memory might be able to be safely swapped to disk.

 

[Jimmah]

Well, set up one Sempron OC'd to 2ghz, tcp heartbeats went from about 575 to 625 which was promising. Added 1gb more ram with stok clock, got up to 605.. It's a start, perhaps a newer architecture at double the clock rate will do better.

Also, I wonder if the built-in NIC's are partly to blame. I have some spare dual-port Intel nics, think it would improve our connections?

Mfenn, great idea, I will try stripping the OS down tomorrow to get the memory usage lower.

I 'think' we're going to try an AM3 quad core, need some results with the stripped OS + OC + more ram before I can go shopping.

 

[mfenn]

Better NICs could reduce CPU load if they support offloading more of the TCP/IP stack. That'll depend on the exact NICS and kernel module versions that you're using though.