Linux bind / dhcp iowait status

[Glenn Satchell]

If you have the opportunity to do it, perhaps you could shut down one
of the main services (dhcp, dns, mysql, etc) for, say, 5 minutes at a
time and see if that made a difference.

regards,
-glenn

>Date: Wed, 15 Mar 2006 14:37:46 -0500
>From: "Tom Greaser" <tgreaser at hsc.wvu.edu>
>To: <dhcp-users at isc.org>
>Subject: Re: Linux bind / dhcp iowait status
>
>also too..
>sorry i dont have the sar data avaliable 
>to go that far back from where i had the 
>phones also running dhcp leases every 4 hours..
>
>but im thinking that didnt seem to make to much of a diff..
>
>
>
>im going to break the mirror tonight and
>see if is a hardware issue..
>
>Thanks again for the echos..
>
> 
> 
>>>>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 ? 
> 
> 
>