Nah, Linux supports up to 1024 cores, depending on the distro. And with TCP offload technology and memory-mapped I/O in modern 10Gbit NICs, you can saturate a 10Gbit link without even pegging a CPU. The linux scheduler has no trouble at all keeping that many processes busy (we have 48-core 512GB boxes that we peg at 100% on a regular basis).
So Linux isn't going to be the scaling issue. The main thing I'm concerned with is what cfservd will do when it is asked to fork 1000+ copies of itself to accept the flood of incoming connections. Linux will diligently schedule the processes to available CPUs, and the NIC will definitely keep up, but will cfservd hit some internal sub-process limit, run out of ports, hit some issue with lock contention, or otherwise not scale up to this level? The most load I've ever put on cfservd has been about simultaneous 500 processes on a single server saturating a 2Gbit link. It worked fine. What happens when I kick up all of the variables by 2-5x? Paul Krizak 7171 Southwest Pkwy MS B200.3A MTS Systems Engineer Austin, TX 78735 Advanced Micro Devices Desk: (512) 602-8775 Linux/Unix Systems Engineering Cell: (512) 791-0686 Global IT Infrastructure Fax: (512) 602-0468 On 04/30/10 11:22, Mark Burgess wrote: > > I think the issue is where Linux can support this many cores. My > understanding was that > the Linux kernel was limited to 8 cores, but this is only hearsay. > > Paul Krizak wrote: >> Has anybody out there ever tried scaling up a cfengine server (v2.1 or >> v2.2) on a really big, fast server? I'm thinking on the order of 4 >> sockets, 24 cores, and a 10Gbit NIC. >> >> This is to support a particularly massive (and temporary) flood of >> cfagent requests to synchronize their local policy. It's going to be a >> lot easier to scale the server up in this case rather than adjust the >> policy to distribute requests to multiple cfservd's. >> >> So what's the experience out there? Can cfservd scale up and keep >> 10Gbit of bandwidth busy? Can it utilize 24 cores? Will it fall over >> or thrash on internal locks trying to run that many threads? >> > _______________________________________________ Help-cfengine mailing list Help-cfengine@cfengine.org https://cfengine.org/mailman/listinfo/help-cfengine
