Linux bind / dhcp iowait status
Tom Greaser
tgreaser at hsc.wvu.edu
Wed Mar 15 19:30:50 UTC 2006
its a dhcpd / dns / mysql local dbase / and apache (last two for
management purposes)
SORRY my bad .. i did have phones set to 5 days...
Thanks.. I was thinking that was kinda high!!!
we have had issues with the hardware mirror before.. and
of course after the fact.. thats when i started getting
sar checks for this kind of data..
I do have
update-optimization false;
the way i rehup dhcpd and dns .. it
overwrites the ddns info.
this way the clients when renewing their leases
will also do a ddns update request.
ls -al dhcpd.leases
-rw-r--r-- 1 root root 2515836 Mar 15 14:26 dhcpd.leases
sleep 60
ls -al dhcpd.leases
-rw-r--r-- 1 root root 2535524 Mar 15 14:28 dhcpd.leases
diff = 19688 (19k)
>>>dhcp at thehobsons.co.uk 03/15/06 12:06 pm >>>
Tom Greaser wrote:
>have a beefy box that shows 18.40 % iowait at PEAK times
>and as low as 5.50 % during work hours..
>
>have 2000 phones lease set to 1 day
>
>2000 pc lease set to 4 hours..
>
>running ddns on this host ...
>
>just wanting to see if this is "normal"
>
>will track down to see if its named or dhcpd doing the bulk of IO
wait..
>
>Its an Redhat AS 4 update 3 box with mirrored scsi Ultra 320 drives
>10000 rpm
>bind-9.2.4-7
>dhcp-3.0.1
>
>from free -h
>buffer 137meg cache 1627 meg
That sounds exceedingly high IF the box is only doing DHCP and DNS.
In fact I'd consider 5.5% to be exceedingly high for such a box.
What else is running on the box ?
Does it make any difference if you increase lease times as Glenn
suggests ?
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