I need to upgrade two VDX6740 switches that form a VCS from 6.0.2b to 7.4.1b.
Since we can reboot the switches, I don’t mind doing a reboot, as long as the configuration is retained.
According to this article (https://extremeportal.force.com/ExtrArticleDetail?an=000076780) it is possible to jump from 6.0.2h to 7.4.1a directly without losing configuration, although release notes from 7.4.1 suggest coldboot is possible only from 7.x. Which one is correct?
Is it possible to upgrade from 6.0.2h to 7.4.1a (or better 7.4.1b) without losing configuration?
Best answer by Mick Day
Upgrade of NOS whilst retaining configuration is only possible one step at a time. i.e. NOS 6.0.2 to NOS 7.0.2 or NOS 7.1.0x to NOS 7.2.0x
In your case to upgrade from NOS 6.0.2h to NOS 7.4.1x would require 6 upgrade steps to retain configuration
NOS6.0.2h → NOS7.0.2x → NOS7.1.0x → NOS7.2.0x → NOS7.3.0x → NOS7.4.0x → NOS7.4.1x
There is multi-version upgrade option which is described in the article you refer to, but in your case with a two switch fabric this would not gain you much time, so a standard step by step upgrade would be best for you.
There are no direct upgrade paths which will retain configuration without using the intermediate versions. The direct approach would only be possible by defaulting the configuration.