Hi William,

Thanks for your reply.

Basically I would like to utilise x86_64 especially since the hardware supports it.

I will be working with hardware that will have 8GB ram. The idea is a VPS will be allocated x amount of ram that should be a hard limit similar to how a normal dedicated server would behave when you hit your physical ram limit.

Disk IO will be fairly moderate, and won’t be beyond fairly standard levels.

-Alan

-----Original Message-----
From: William Pitcock [mailto:nenolod@xxxxxxxxxxxxxxxxxx]
Sent: Thursday, 7 August 2008 12:15 PM
To: Alan Lam
Cc: venefax; xen-users
Subject: RE: [Xen-users] Xen Setup

Hi,

On Wed, 2008年08月06日 at 18:03 -0700, Alan wrote:

> We don’t do anything fancy really, just the straight out VPS like no

> other. We don’t map PCI devices to VPSes etc. It really is just an OS

> on a disk with a memory allocation.

>

> 

>

> Considering you have both, would you be able to give a brief

> advantages/disadvantages between using OpenVZ and Xen? I have been

> considering OpenVZ as well as Xen and Xen was looking a little better

> on the IO performance side.

>

Xen has no real advantages over Virtuozzo with I/O, although it is very easy to integrate SAN solutions like ATA-over-Ethernet and iSCSI. I have a fairly large cluster mostly fed by an ATA-over-Ethernet meshed SAN, and the performance is quite acceptable.

> 

>

> Thing is, we would like to be able to take advantage of the fact the

> CPU can handle 64bit and would like to run a 64bit Xen host along with

> 64bit VPSes. I am not sure if Xen can do this or not, nor whether

> OpenVZ can either.

>

Roughly 98% of my customers are on x86-64 instances. Approximately 20 are still on x86-32 instances. All of our dom0's except for one node is

x86-64 capable (dual Opteron 2216 hardware from Rackable Systems).

Personally, I have found that Xen's behaviour is a lot more reliable on

x86-64 than it is on x86-32. But maybe that's just my setup.

> 

>

> If you look at my original post to the mailing list, we are

> considering the switchover because of new hardware/newer OS.

>

What hardware do you have? Virtuozzo's memory overcommitting would probably be useful to you if you are working with lowspec hardware (<= 8GB). I know that with Xen, we have reached capacity limits a few times because the customer growth was increasing more rapidly than we could order and rack more hardware for the clusters.

Furthermore, anything I have said about Virtuozzo can be applied to OpenVZ without much difficulty.

William