Posts tagged HP VIRTUAL CONNECT

HP Virtual Connect Smart Link

6
August 5, 2009
by Michael McNamara in

hpweb_logoHP’s Virtual Connect supports a feature called Smart Link, a network enabled with Smart Link automatically drops link to the server ports if all uplink ports lose link. This feature is very similar to the Uplink Failure Detection (UFD) that is available on the HP GbE2, GbE2c and most ProCurve switches. I believe there is a similar feature available on Cisco switches called Link State Tracking.

You might be asking, so what. Well a reader recently mentioned Smart Link in conjunction with my post concerning HP Virtual Connect & vSphere 4 so I thought I’d post some of my thoughts about Smart Link. It’s seems redundant to me given the presence of LACP but let me explain.

From a Nortel perspective you can connect two NICs from a single server to a Nortel switch cluster, two ERS 5500 or 8600 switches, using LACP and get a  “802.3ad Dynamic with Fault Tolerance” configuration. This essentially provides an active/active solution utilizing both NICs to their fullest. LACP is used to determine network path failures.

From a Virtual Connect perspective the same applies as above. The Virtual Connect Ethernet interconnect modules act as a single switch fabric allowing you to create a “802.3ad Dynamic with Fault Tolerance” configuration providing an active/active solution. While you can do this to servers you can’t span external uplinks across interconnects out of the enclosure in an active/active configuration.

In the old days you’d only get a “Transmit Load Balancing with Fault Tolerance” or “Network Fault Tolerance” configuration when your server NICs spanned two switches. This essentially provided an active/standby solution. Network Fault Tolerance only uses link status as a determinator to whether the network is functional or not. In order to detect a failure the server would need to see a link loss on the primary NIC before failing over to the standby NIC. Smart Link provides the ability to shutdown the server switch ports if all the uplink switch ports go down so the NIC teaming configuration can detect the link status change on the server and fail-over to the standby NIC which would be cabled to a different network switch.

In this case it would appear to me that LACP has really replaced what I would describe as a legacy feature, Smart Link. You can have multiple external uplinks out of an enclosure spread across multiple interconnects. While only the external uplinks on a single interconnect will be active, any remaining uplinks on any other interconnects will be in a standby mode.

I’m telling this as I see it, I’m no expert concerning Virtual Connect by any means so please tell me if I’m wrong!

Thoughts?

References;
http://blog.michaelfmcnamara.com/2009/01/hp-nic-teaming-with-nortel-switches/
http://www.michaelfmcnamara.com/files/TeamingWP.pdf

HP Virtual Connect & VMware vSphere 4

2
August 2, 2009
by Michael McNamara in

HP 7000 EnclosureAs I’ve mentioned in the past we’re kicking off a very large endeavor to move a significant number of our servers to a virtual environment. Over the past two weeks we built out an HP 7000 enclosure with 4 HP BL460c server blades, 6 HP Virtual Connect 1/10 Gb-F Ethernet interconnects, and 2 HP Virtual Connect 8Gb 24-Port Fiber Channel interconnects. The purpose of this hardware is to provide a temporary staging location as we perform the physical to virtual conversions before moving the virtual machines (across the network) to a new data center where additional VMware vSphere 4 clusters will be waiting.

We had some small issues when we first turned up the enclosure but the biggest hurdle was our unfamiliarity with Virtual Connect and locating the default factory passwords (we had ordered the enclosure as a special build so it came pre-assembled which saved us a lot of time and effort and was well worth the small added cost).

We’re currently using two Nortel Ethernet Routing Switch 5530s in a stack configuration mounted at the top of the rack. We also have a Nortel Redundant Power Supply Unit (RPSU) 15 installed to provide redundant power in the event that we loose a one of the rooms UPS’s or that we have an issue with an internal power supply in either ERS 5530 switch.  We load software release 6.1 onto the ERS 5530s and so far haven’t observed any issues. We’re initially connecting the ERS 5530 stack via 2 1000BaseSX (1Gbps) uplinks distributed across both ERS 5530 switches (DMLT) to a pair of Nortel Ethernet Routing Switch 8600s running in a cluster configuration using IST/SMLT(SLT) trunking. As the solution grows we can expand the uplink capacity by adding additional 1Gbps uplinks or by installing 10Gbps XFPs. We’re downlinking from the ERS 5530 stack to multiple HP Virtual Connect 1/10Gb-F modules using LACP. Unfortunately you can’t have a LAG span multiple HP Virtual Connect 1/10Gb-F Ethernet modules as this time. If you do, only the ports on one of the modules will be “Active” while the ports on other modules will by in “Standby”.

hpvirtualconnect110gbfThe HP Virtual Connect 1/10 Gb-F Ethernet interconnects provide 16 Internal 1Gb Downlinks,  4 External 10/100/1000BASE-T Uplinks, 2 External 10/100/1000BASE-T SFP Uplinks, 2 External 10Gb XFP Uplinks, 1 External 10Gb CX-4 Uplinks, and 1 10Gb Internal Cross Connect. Using the internal 10Gbps cross connect along with the external 10Gb CX-4 uplink you can create a 10Gbps network within the enclosure. You can also link multiple enclosures together to form a 10Gbps network contained entirely within the rack. This could be very beneficial in keeping vMotion and other unneeded traffic off the core uplinks.

In testing we did run into a significant problem that already appears to have been documented by HP although a solution is yet to be formulated. In testing several failure scenarios (physically removing the HP Virtual Connect Ethernet interconnects or remotely powering them down) we observed a significant problem when the interconnects where restored. The HP Virtual connect 1/10Gb-F would show no link to the blade server while the VMware 4 console would indicate that there was link. This problem obviously affected all traffic associated with that port group. The solution was to either reboot the VMware host or reset the NIC using ethtool -r  {NIC} from the server console.

Here’s the excerpt from the release notes;

When a VC-Enet module is running VC v1.30 firmware or higher, a link might not be re-established
between the module and the ports of an NC364m mezzanine card under the following conditions:

  • The network mappings are changed on the NIC ports through Virtual Connect.
  • The VC-Enet module is restarted from a power-cycle or reboot, or the module is removed and inserted.

If the server is rebooted, the link is established on all ports on both sides of the connection. Manually
toggling the link from the server should also restore the link.

The jury is still out on HP’s Virtual Connect although I hope to dig deeper in later posts.

Cheers!

References;

http://h18004.www1.hp.com/products/blades/components/c-class-interconnects.html

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c01730696/c01730696.pdf

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