[lvs-users] Are LVS / ldirectord Multithreaded?

Graeme Fowler graeme at graemef.net
Fri Oct 31 22:52:13 GMT 2008


Hi

On Fri, 2008-10-31 at 14:57 -0700, Robinson, Eric wrote:
> > What sort of packet throughput are you getting? 
> 
> How would you like that measured?

Packets/sec in and packets/sec out on the director is usually a good
bet :)

> > Are you using LVS-DR or LVS-NAT? 
> 
> LVS-NAT

Right... NAT makes the CPU work harder than DR because, well, it's doing
more work. If that isn't self-evident, say so, and I'll explain further.

> Aside from running heartbeat and ldirectord with 100+ virtual servers,
> not too much. Here's the output from top:
> 
> top - 13:43:47 up 81 days,  9:12,  1 user,  load average: 1.40, 1.42,
> 1.38
> Tasks:  60 total,   1 running,  59 sleeping,   0 stopped,   0 zombie
> Cpu(s): 46.8% us,  3.0% sy,  0.0% ni, 48.8% id,  0.0% wa,  1.3% hi,
> 0.0% si
> Mem:    516304k total,   506348k used,     9956k free,    45448k buffers
> Swap:  1048568k total,        4k used,  1048564k free,   369656k cached
> 
>   PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>  2762 root      17   0 13708 9884 1744 S 50.4  1.9  13386:29 ldirectord

Whoa there, horsey!

81 days uptime is 116640 minutes; that means ldirectord has consumed >
10% of the CPU in the time the server's been up. What's the health check
interval here?

With (say) 100 virtual servers, 2 realservers each, an interval of 10
seconds means 200 checks every ten seconds (nominally). Assuming a 0.1
second latency for each check, you're talking overlapping checks there
so a given check thread is only half way through running when it starts
again.

I can see some tuning being required here - or trying to make ldirectord
fork and thread correctly (if it doesn't already). Horms, can you
comment here?

Graeme





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