stacking 2 HP Procurve 2910al switches

[Scott Kusko]

We are currently in the process of stacking 2 HP Procurve 2910al switches. What I would like to know is if it is possible to create an "Etherchannel" using 2 ports on one Switch and 2 ports on the other Switch. Is that possible in the HP world?

[Richard Brodie_1]

Yes.

http://cdn.procurve.com/training/Manuals/2910-MCG-Feb09-12-PortTrunk.pdf

[Mark Wibaux]

"Stacking" in the HP E series (Procurve) world is purely a management stacking function allowing you to use a single IP address to access multiple switches in the stack for management only.

I assume you are thinking of stacking from a Cisco point of view whereby you have dedicated proprietary cables joining 2 or more switches together. Once the stack is created that allows you to treat it as a single big switch. On the Cisco this would then allow you to configure port 1 on switch 1 and port 1 on switch 2 as an etherchannel that would then connect to either another switch or to a server.

Unfortunately in the HP world that is not possible with the switches you have. You need to move to a Provision based unit (3500, 6200, 6600, 5400zl or 8212zl). With these switches you have an option called Distributed Trunking which would allow you to do what you want with LACP based trunks but only to servers (it doesn't work with connections to other switches). There are also other limitation to do with routing etc.

The other option in the HP world is the A-series gear (what come out of the aquisition of 3Com/H3C). These switches have a feature called IRF which is similar to the Cisco stacking but instead of using proprietary connections they use the standard 10GbE ports to link the "stacked" switches together. You can then create BAGGs (Bridge Aggregation Groups) that can span ports on different switches in the stack.

[Richard Brodie_1]

After reading Mark's post, I'm not so sure what you were asking. You can trunk the switches together but (as he says) you can't create a distributed trunk (what Cisco apparently calls a Multichassis Etherchannel).

[Scott Kusko]

Thanks guys. What we are trying to do is maximize bandwidth to our SAN's. We wanted to try and throw 8GB at it, all at once. These are currentl connected to HP2910al's.

[Mark Wibaux]

What sort of iSCSI SAN is it?
What are the host OSes on the servers?

These all affect how you configure things. For example if you have HP Lefthand nodes then you wouldn't worry about trunking to the nodes. You would just configure a ALB bond with the NICs, connect it to both switches and let it handle the load balancing of the links. If the hosts were running vmware ESX then you would configure a vswitch with multiple NICs going to both switches and then create a VMKernel port for each NIC in the vSwitch. Each vmk would have its own IP address and then be bound to the iSCSI software HBA. ESX would then multipath and balance the load across the host links (assuming you set it up for Round Robin Access to the iSCSI LUNs).
As for other vendors I'm sure they have their own best practices for configuring this sort of stuff.