Barry Abrahamson barry at
Tue Apr 14 19:59:58 MSD 2009

On Apr 13, 2009, at 10:05 AM, russlndr wrote:

> HP Blades with AMD CPU support up to 128 GB of RAM. We have 3 x AMD  
> with 128 GB and 3 x Intel 64 GB. The new intel HP blades support 144  
> At peak each varnish server is handling 40k established connections,  
> not active connections as I wrote by mistake. About 7000 to 8000  
> hits per second.

Are you also using nginx in this setup?  We are using nginx + varnish  
for (nginx --> varnish --> apache ) and are  
running into issues with the nginx boxes getting CPU bound (softirq,  
not user).  We are only able to get about 8000 req/sec (1k est  
concurrent TCP connections) per nginx server before this happens.   
Anyone else seeing this at high concurrency?  We have already done the  
obvious stuff like disable connection tracking, and are using  
irqbalance to push the interrupt handlers from eth1 and eth0 onto  
separate cores.  We are running Debian Linux Sarge (2.6.18) 64-bit.   
Any suggestions?

Barry Abrahamson | Systems Wrangler | Automattic

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