RE: [Xen-users] RAID10 Array

Thanks Rob,

I guess I'll just have to get the money together first :)

So I will try out both the 802.ad method as well as the AoE "Load Balanced" method..

Thanks

Jonathan

From: Robert Dunkley [mailto:Robert@xxxxxxxxx]
Sent: Thu 17/06/2010 14:33
To: Jonathan Tripathy
Cc: kriegisch@xxxxxxxx
Subject: RE: [Xen-users] RAID10 Array

Hi Jonathan,

Theoretical would be 2Gbit to the Nodes and 4Gbit to the Storage so 2 nodes could for example get 2gbit bandwidth each simultaneously but this does come with some loss in practice and additional CPU overhead.

The ATA load balance type situation described in the previous email allows 1gb to any one node from a single device on the storage server but up to 4 nodes could drag 1gbit each simultaneously from the storage server. Considering how many nodes you are planning the load balanced scenario might even be preferable to LACP/802.3AD as long as the ATAoE target software can do a good job due to potentially lower CPU overhead and easier implementation of multiple switches for redundancy.

None of these software decision will affect your hardware choice so its portably about time you got your hands dirty J

Rob

From: Jonathan Tripathy [mailto:jonnyt@xxxxxxxxxxx]
Sent: 17 June 2010 14:19
To: Robert Dunkley; xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] RAID10 Array

Hi Rob,

And if I was to use let's say 4 teamed ports coming out of the storage server, and 2 teamed ports going into the xen node, would the max I'd get be still 1Gbit?

Thanks

From: Robert Dunkley [mailto:Robert@xxxxxxxxx]
Sent: Thu 17/06/2010 14:15
To: Jonathan Tripathy
Subject: RE: [Xen-users] RAID10 Array

Hi Jonathan,

LACP and 802.3AD are used together on those HP Soho switches. I might be wrong but LACP I think allows automatic negotiation to some degree at the switch side.

I have used LACP with Broadcom based NICs in Windows and the HP switch you are looking at. You only need to enable LACP on the switch ports plugged into your disk box and then the software on the server should be able to sort the rest (I enabled it with Broadcom NICs under Windows and it worked as advertised).

Rob

From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Jonathan Tripathy
Sent: 17 June 2010 14:07
To: Adi Kriegisch; xen-users@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-users] RAID10 Array

From: Adi Kriegisch [mailto:kriegisch@xxxxxxxx]
Sent: Thu 17/06/2010 14:03
To: Jonathan Tripathy
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] RAID10 Array

Hi!

> Looking at this page https://help.ubuntu.com/community/HighlyAvailableAoETarget
> they seem to have made a linux "bond" called bond0 and are telling the AoE
> target to use that. This confuses me...
> Would it be of any benifit to create a "mode 4" bond and use 802.3ad with ATA
> over Ethernet? Or would that be just a waste, when AoE can use the interfaces
> directly?
ggaoed for example can handle multiple interfaces in the configuration and
is designed to deliver highest performance with for example automatically
load balancing over several NICs.
If you want to use vblade you might be better off using bonding because
vblade cannot handle several interfaces in one instance. You'll get another
performance penalty when using several instances of vblade listening on
different interfaces.
I am not sure if LACP enhances performance in your case: I think from one
server to the other you will only get 1GBit; for LACP to work as expected
you need many-to-many or many-to-one connections. All pakets belonging to a
connection will use the same wire. This article has some
details: http://serverfault.com/questions/8512/multiplexed-1-gbps-ethernet
also Wikipedia has some information on this.

Another thing is that you loose the ability of having a redundancy in the
switching backend.

-- Adi

-------------------------------------------------------------------------------------------------------------------

So if I use ggaoed and just put all 4 NICs into its config file, that should allow me to get 4Gbit of bandwidth? And no configuration is required on the switch?

BTW, does 802.3ad "mode 4" use LACP? Or I am getting mixed up?

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