Interconnect with HP-APA and switches

[Innopath Support]

Hello Forum,

I have 2 RP440 servers in a clusterware configuration, using Back-to-back interconnect. under the interconnect configuration I have HP-APA for NIC redundancy. I think the B-to-B is giving some communication problems and need to upgrade with switches in the middle. I wish to keep HP-APA and for redundancy purpose, I will install two switches.
My questions is:
Is there a specific type of switch that I need to use?
in this case each of the ports from the HP_APA configuration will go to a two different switches, should I need to do anything on the switches to support the APA configuration on the servers?

Thanks,

[Steven E. Protter]

Shalom,

APA is pretty flexible, works with different vendors, even unmanaged switches. A lot of people report good results with Cisco managed switches. Some Cisco work is required to get them to accommodate one ip address on two switch ports.

The doc on that needs to come with Cisco, I know it needs to be done, not how.

SEP

[Court Campbell]

It depends on whether you want to use apa for failover, or if you want to do trunking. If you are only looking for failover (LAN Monitor) then I would think any name brand switches would be fine. If you want to do trunking the switches will have to support MANUAL MODE (not sure of vendors), FEC (FEC/PAgp - this would be cisco) or LACP (cisco & others).

If you find a switch that supports MANUAL configuration then you should not have to do anything to the switch. The switches will only need to be configured if you are going to use FEC/PAgp or LACP modes. You will need to read the vendor docs for the configuration steps.

[Ben Dehner · Accepted solution]

The only way you can use APA with two different switches is with a failover, or manual mode. LACP and FEC, in general, have to go to the same switch, unless you're playing some proprietary vendor games. Nortel, for exmple, only supports a split trunk when using their proprietary MLT (multi-link trunk) protocol, and not with LACP.

Someone correct me, but I think that, in manual mode, each NIC has its own MAC address, but the system does a round-robin reply to ARP requests. Doesn't help much if most of your traffic is out of the subnet, and all the ARP requests all come from the gateway router, which will probably query once then hold it in cache. LACP and FEC both create a virtual MAC address for the trunk; this will cause lots of problems in layer-2 land when the various fowarding databases start showing the same MAC address on different switches.

We used stacked Nortel switches. My preferred configuration is primary LACP group that goes to one stack -- but different switches in the stack -- and a failover LCAP group that goes to a secondary switch stack.

[Innopath Support]

Thanks all for the great feed back.

I check with HP support and their response was that I can NOT use APA configuration on loadsharing mode and two switches. The only and probably the best option is to use APA with Hot-standby mode which will do a failover function the same way LanMonitor does. this option does not required any configuration on the switch while making the configuration changes on the on the servers will be rather easy.
on

/etc/rc.config.d/hp_apaconf
set parameter:

HP_APA_HOT_STANDBY[0]=ON

[rick jones]

While you cannot do "meshing" today, that doesn't mean it wouldn't be a good idea to excercise the support contract and have a bug/enhancement request filed against APA to have such support added in the future.

What sort of communication problems were you seeing that has you wanting to go from a back-to-back config to a switched config?

For some switch ideas, http://www.hp.com/go/procurve :)

[Innopath Support]

I am running Oracle 10G with RAC cluster. After March 11 DST patches I had several incidents of lossing interconnect communication causing RAC to reboot one of the nodes.
Later I learn that Back-to-Back interconnect is not supported by Oracle which is what is forcing to upgrade the hardware.