Subject: Re: [vserver] Pros and Cons of 32/64bit guests on 64bit host
From: Nicolas Cadou <ncadou@cobi.net>
Date: Thu, 21 Aug 2008 10:22:46 -0400
Thu, 21 Aug 2008 10:22:46 -0400
Le August 20, 2008, Oliver Welter a écrit :
> I am running vserver on 32bit boxes for years now. I am know replacing
>  one group of nodes with nice Dual AMD Quad-Cores which run a 64bit
>  debian host OS.
>
>  As I have to update the guests anyway (I used and will use gentoo for
>  them), so I am considering to move them to 64bit, too. The guests are
>  several LAMP servers, mysql and postgres and a set of qmail nodes.
>
>  The only issue that is an obvious go for 64bit would be memory segments
>
>  >3GB, but I guess I wont have guests who use it. So, anybody here can
>
>  give pros and cons for 32/64 bit guests?

I recently moved my 32 bit vservers from an Intel 32 bit host over to a brand 
new Intel 64 bit box. The host is Ubuntu Server 64 bit, but there is no 
vserver-enabled kernel in Hardy, so there is a twist. 

The 64 bit host now happily runs several virtual machines (of the KVM kind), 
some Windows, some Linux, and a SCO OpenServer is coming down the pipe. One 
VM is a Debian Etch 32 bit vserver host, into which I moved all the vservers 
from the old 32 bit host, now decommissioned.

The migration was flawless, and everything is running smoothly since then, 
with one notable exception:

After a few weeks of uptime, the MySQL server (5.0) in one of the vservers 
stops accepting TCP connections, blurting out timeout error messages that 
normally occur after several seconds when in real connection timeout 
conditions.

The connection errors happen instantly at connection time, and adjusting the 
MySQL configuration settings, restarting the MySQL server or even the vserver 
itself doesn't help a bit.

The only remedy to this condition is to restart the KVM virtual machine 
hosting the vservers.

So maybe that VM should run the 64 bit version of Debian Etch, not the 32 bit 
version as it does now. I don't know, and I don't have the time to change 
that anyway so I'm living with the slight inconvenient of restarting the VM 
once in a while.

-- 

Nicolas Cadou

Cobi Informatique Inc.
Tel: (450) 266-2420 (305)
Fax: (450) 266-2415


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