VSS redundancy force-switchover

[mpellegrino12]

Have two cat6500 in VSS. With single SUP 720-10G in each chassis. 

If I were to perform a redundancy force-switchover command to fail over to standby SUP which is in the other chassis.

1. What happens to the former active SUP. Is it reloaded?

2. What happens to the line cards in the chassis of the former active SUP. Are they all reloaded as well?

[Leo Laohoo]

When the command "red force" is entered, the primary supervisor card reboots (and the entire chassis reboots as well).
When the primary supervisor card reboots, the secondary card automatically becomes primary.
The supervisor card that has reboot then joins the VSS and becomes the secondary.

[mpellegrino12]

Thanks Leo. Is there any way to failover gracefully without it rebooting the sup and chassis?

[Abheesh Kumar]

No you cannot, as per the VSS architecture it will get reloaded when you swithover to other SUP.

HTH
Abheesh

[mpellegrino12]

Awesome thanks for the info. Just 2 quick question,that I'm just curius about.

1. If this was a single chassis with 2 SUPs not it VSS and I forced a switch over. Would it still reboot the chassis?

2. If I had quad SUP setup in VSS, 2 SUPs in each chassis and I forced a failover. Would it still failover to the other chassis or would it failover to the other SUP on the same chassis? Again would it reboot the line cards?

[Abheesh Kumar · Accepted solution]

Hi,
1. Single chassis with 2 Sup and not in VSS will not reboot the entire chassis.
2. For QUAD SUP it will failover to other chassis.

In-chassis active (ICA) supervisor engines—The VSS active supervisor engine in one chassis and
the VSS standby supervisor engine in the other chassis are ICA supervisor engines.

If the VSS active ICA supervisor engine crashes, a switchover to the standby ICA supervisor engine
in other chassis occurs. Both VSS chassis remain active. All switching modules remain active.

In the chassis with the previously active ICA supervisor engine, an SSO switchover from the
previously active ICA supervisor engine to the ICS standby supervisor engine occurs and the ICS
takes over as the ICA. The failed ICA reloads and becomes the ICS.

 In-chassis standby (ICS) supervisor engines—The other supervisor engines are ICS supervisor
engines. The supervisor engine uplinks ports are available to forward traffic.

Below doc for your reference  Page 11-9

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst6500/ios/15-2SY/config_guide/sup2T/15_2_sy_swcg_2T/virtual_switching_systems.pdf

HTH

Abheesh

[Leo Laohoo]

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@mpellegrino12 wrote:

Thanks Leo. Is there any way to failover gracefully without it rebooting the sup and chassis?

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This is possible only when the VSS "scenario" is quad-supervisor card (two per chassis).  Otherwise, no.  Once the Supervisor card reboots, all the line cards in the same physical chassis reboots.

[ShahrulEzwvn]

can be done using redundancy force-switchover?

failover standby to active without reloading it, using QUAD SUP.

[Leo Laohoo]

I am not sure but promoting standby to active, in a quad sup, should not reboot all the other line card.  

[ShahrulEzwvn]

i see, it can be done gracefully.