5520 HA Code Upgrade Question

[Ryan Curry]

Hi all, I'm looking to do my first upgrade on my 5520 HA pair.  The pair in question is for a hospital campus so, as you can imagine, uptime is crucial.  The upgrade will take place at night, but I still need to minimize the downtime.  My question is if I can perform a restart (soft reload) or do I need to actually do a reset (hard reload)?  The documentation says to schedule a reset, but in my experience it takes quite a bit of time just to get the server bounced to even start the WLC software loading.

TIA!

Ryan

[M. Wisely]

So the documentation says to schedule a reset, it means a reset not a restart as you cannot schedule a restart.

[Ryan Curry]

Thank you for your input, but the reason it says to schedule is to avoid having a version mismatch between controllers.  My question is if anyone has performed a restart in the field and run into any issues.

[Scott Fella · Accepted solution]

I have done this on many sites and with the 5520 it takes about 10min before everything comes back up.  You will do a reset, but I would issue the reset system both in <time> and specify 5 min or 10 min.  Also make sure you pre download the image to all AP's so reduce the downtime.  One thing I would do is if you run a Microsoft DHCP server is to monitor the AP dhcp scope and verify that there are no bad addresses when you initiate the upgrade. 

-Scott 

*** Please rate helpful posts *** 

[Ryan Curry]

Thanks Scott, I've already got it all set with the APs pre-downloaded and images swapped.  I've also gone through and issued a reset system both at <time> for my 1:00 am upgrade schedule.  Again, since I've not done an upgrade in production with this configuration, I don't know what to expect from a downtime.  10 minutes is acceptable, 25 - 30 minutes (which is what I was worried it might take) is a completely different situation.

As for DHCP, we use the BlueCat IPM which has always been reliable.

Thanks again!

[Scott Fella]

I have upgrade site with 400 some AP's and everything came back within 10 minutes. The dhcp bad address is only with Microsoft dhcp so you are good.  I would have console connection to each so you can at least monitor and have a good understanding of what happens for future reference.

-Scott 

*** Please rate helpful posts *** 

[Ryan Curry · Accepted solution]

Just a quick follow up, not that you need the verification Scott, but you were 100% correct.  The downtime was less than 10 minutes and all came back as expected - thanks for the validation!

[Scott Fella]

Thanks for the follow up. This helps others also when they have concerns about the time it takes for an upgrade.

-Scott

*** Please rate helpful posts *** 

[UWStoutTelecom]

Question on the windows dhcp,  we have windows dhcp server2008 and have the bad address issue, in reading I found this command(config ap dhcp release-override enable {cisco-ap | all})

as a work around and was wondering how well it works.

Dean