WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-users

Re: [Xen-users] small cluster storage configuration?

To: Miles Fidelman <mfidelman@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] small cluster storage configuration?
From: Bart Coninckx <bart.coninckx@xxxxxxxxxx>
Date: Mon, 10 Oct 2011 09:24:52 +0200
Cc: "xen-users@xxxxxxxxxxxxxxxxxxx" <xen-users@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 10 Oct 2011 00:26:54 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4E921F8A.5070406@xxxxxxxxxxxxxxxx>
List-help: <mailto:xen-users-request@lists.xensource.com?subject=help>
List-id: Xen user discussion <xen-users.lists.xensource.com>
List-post: <mailto:xen-users@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <4E921F8A.5070406@xxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1
On 10/10/11 00:26, Miles Fidelman wrote:
Hi Folks,

I've been running a 2-node, high-availability cluster for a while. I've
just acquired 2 more servers, and I've been trying to figure out my
options for organizing my storage configuration.

Basic goal: provide a robust, high-availability platform for multiple
Xen VMs.

Current configuration (2 nodes):
- 4 drives each (1TB/drive)
- md software raid10 across the 4 drives on each machine
-- md devices for Dom0 /boot / swap + one big device
-- 2 logical volumes per VM (/ and swap)
-- VM volumes replicated across both nodes, using DRBD
-- pacemaker, heartbeat, etc. to migrate production VMs if a node fails

I now have 2 new servers - each with a lot more memory, faster CPUs (and
more cores), also 4 drives each. So I'm wondering what's my best option
for wiring the 4 machines together as a platform to run VMs on.

Seems like my first consideration is how to wire together the storage,
within the following constraints:

- want to use each node for both processing and storage (only have 4U of
rackspace to play with, made the choice to buy 4 general purpose
servers, with 4 drives each, rather than using some of the space for a
storage server)

- 4 gigE ports per server - 2 reserved for primary/secondary external
links, 2 reserved for storage & heartbeat comms.

- total of 16 drives, in groups of 4 (if a node goes down, it takes 4
drives with it) - so I can't simply treat this as 16 drives in one big
array (I don't think)

- want to make things just a bit easier to manage than manually setting
up pairs of DRBD volumes per VM

- would really like to make it easier to migrate a VM from any node to
any other (for both load leveling and n-way fallback) - but DRBD seems
to put a serious crimp in this

- sort of been keeping my eyes on some of the emerging cloud
technologies, but they all seem to be aimed at larger clusters

- sheepdog seems like the closest thing to what I'm looking for, but it
seems married at the hip to KVM (unless someone has ported it to support
Xen while I wasn't looking)

So... just wondering - anybody able to share some thoughts and/or
experiences?

Thanks very much,

Miles Fidelman



DRBD does not do 4 nodes. If you split in two clusters you cannot cross migrate, unless you set up the storage on each node in some way, bu thow are you going to replicate?

Personally, I would create a storage cluster and a VM cluster, allowing for epxansion of the virtual nodes later if time/budget permits.

B.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users