slow "KVM Host" in EL6 ?

[Ben]

On Fri, 13 May 2011, Paul N wrote:

> On Thu, May 12, 2011 at 3:30 PM, Ben <bda20 at cam.ac.uk> wrote:
>> On Thu, 12 May 2011, Dmitry Makovey wrote:
>>
>>> we have some weird problem with EL6 box which serves as a KVM host for 3
>>> VMs currently. It shares the same interface with all 3 VMs (same network).
>>> All works, except from time to time machine behaves very slow in console
>>> (ok, SSH connection) and it happens only from time to time.
>>> [...]
>>
>> It may be unconnected but I have a RHEL6 box which also occasionally has 
>> an issue with slow SSH connection.  By that I mean you type "ssh 
>> rhel6host", the password prompt comes up quickly, but after entering the 
>> password and hitting return there's a palpable delay (sometimes) before 
>> the prompt appears.  Not every time, but often.  Sometimes as long as 
>> four to five seconds.  A RHEL6 KVM guest I installed on it also has the 
>> same issue (sometimes).  I've run ssh with -vvv and sshd with -vvv and 
>> not seen anything untoward.  DNS is on the local LAN and reports no 
>> issues either. All connections are from RHEL5 hosts.  Just somtimes 
>> connection is... slow.
>
> I've seen the problem you've described when I have a bogus entry for 
> localhost (or an incorrect IP address for the server's FQDN) in 
> /etc/hosts. YYMV of course!

/etc/hosts:

10.1.1.158      knife.internal.admin.cam.ac.uk  knife   # Added by NetworkManager
127.0.0.1       localhost.localdomain   localhost
::1     knife.internal.admin.cam.ac.uk  knife   localhost6.localdomain6 localhost6

Ben
-- 
Unix Support, MISD, University of Cambridge, England
Plugger of wire, typer of keyboard, imparter of Clue
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