topic Re: Moving Network between Uplink Sets - Downtime? in HPE Synergy

Moving Network between Uplink Sets - Downtime?

Shakedown1979 — Thu, 14 Jan 2021 08:54:18 GMT

Hi there all,

I have a requirement to move a single Network between different Uplink Sets on a number of Logical Enclosures. Simple question I guess - would this be a seamless task on the F8, resulting in zero downtime? The uplink network fabrics are different, but entirely routable and L3 is currently on the desired target of the Synergy Network move; we wish to demise the current Uplink Set.

I understand that adding, or removing, Networks from an Uplink Set which is not in-use should be seamless, and indeed has proven to be so, but moving a Network which is in use, I am unsure.

Cheers for any feedback!

Re: Moving Network between Uplink Sets - Downtime?

AkilDevaraj — Fri, 15 Jan 2021 11:11:42 GMT

Hello ,

Thank you for the question posted.

Since we are moving or editing a network set which is in use there would be a partial outage or network disruption in this case , the compute modules will be using these connection/network sets which will cause a network outage for the hosts while moving the network sets in use.

Hence would suggest to have a downtime and move the network sets .

https://techlibrary.hpe.com/docs/enterprise/servers/oneview5.0/cicf/en/index.html?textToSearch=network+#s_networkset-delete.html

https://assets.ext.hpe.com/is/content/hpedam/a00042387enw

Thank you

Re: Moving Network between Uplink Sets - Downtime?

ChrisLynch — Fri, 15 Jan 2021 17:38:37 GMT

Well, when you move a VLAN configuraton from one switch port to another, the ASIC needs to update its forwarding table. And in doing so, there is the possibility of losing some traffic. So, I would suggest you only target 1 Uplink Set at a time to move. But if you have an MLAG configuration where you have a single uplink set with ports from both VC F8 modules, you will likely experience a slight outage while switches learn source and destination MAC address have moved. I would plan this change for non-peak usage just in case. And potentially schedule downtime just in case there is a small outage experienced.

Re: Moving Network between Uplink Sets - Downtime?

Shakedown1979 — Fri, 15 Jan 2021 18:12:53 GMT

Smashing - thanks for the responses. We do indeed use MLAG between the F8s in 2 of the 3 Encs in the LEs, with uplink Cisco ACI fabric. The particular network being moved between uplink ports is a static tagged vlan used for some of our VMware VMKernel mamagement NICs, nothing else is planned to be changed between the Uplink Sets, so providing the slight downtime is purely with that one (_?) I think we should be good.

Re: Moving Network between Uplink Sets - Downtime?

Shakedown1979 — Sat, 20 Mar 2021 19:21:18 GMT

Will mark this one as solved, many thanks!

Thankfully I did raise an outage, thought I would share the results as I wasn't entirely sure what to expect and others may have a similar question in future.

Within OneView you get the usual confirmation message to accept what you are about to do could be disruptive to connectivity, and indeed it is, but with careful planning major issues can be avoided. Shortly after applying the configuration connectivity to the moved vlan goes down, and stays that way for approximately 9-12 minutes I found - I had a number of LEs to complete this work on and all completed in around that time.

As you stated, working on a single Uplink Set at a time and migrating workloads around prevents any serious outages.