slow "KVM Host" in EL6 ?

[Ben]

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.

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