Performance issue ( maybe )
TomSchmitt at gmx.de
Mon Sep 6 07:01:07 UTC 2010
> Von: Bjarne Blichfeldt <bjb at jndata.dk>
> Betreff: Performance issue ( maybe )
> During clients startup, the servers takes a very long time ~20-30
> seconds> to answer a DISCOVER.
As a first step before you look for the source on the server, I would do a tcpdump on the server interface to make sure that the delay you are experiencing are really originate there and not somewhere else on the network.
> è Cpu2 : 0.0%us, 0.3%sy, 0.0%ni, 1.3%id, 98%wa, 0.0%hi, 0.0%si,
So regarding the wait I/O: first step is looging without sync, second step is logging only errors and higher third step is no logging at all (only for a testperiod to see if your problem is going away)
> The only process really working is kjournald.
So are ther any other logmessages in high numbers beside the ones from dhcpd?
> 1) anybody seen something similar ?
> 2) Good ideas to further investigate ? What about the network
> topology ? Any gotcha's when sending DISCOVERY through two cisco routers ?
Shouldn't be an isuue. I do the same without having problems.
Or did you you just upgrade your IOS?
Is the problem occuring on both on your dhcpd-servers at the same time? Or only on one of them?
And are there any messages in the log which could give you a hint?
> Also, what would be the consensus of disabling pingcheck ?
> ping-check false;
> The ping adds at least one second to every discovery/offer,
You would win one second, but haveing other problems. I won't recomment it. Better you find the real problem than working around it.
> option option-150 10.11.75.10 ;
> filename "\\mboot.0<file:///\\mboot.0>" ;
> next-server 10.2.2.240 ;
Could it be, that not your server is the source of the problem, but the server 10.2.2.240?
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