3750 IOS upgrade downtime

[Alvin Lalisan]

Hi,

Will their be a service interruption during software upgrade to a switch? How long?

thanks regards,

AL

[vivek srivastava]

Yes. Switch will reload and converge.

If everything is ok, then need approx 10-15 min of downtime.

[Leo Laohoo]

Will their be a service interruption during software upgrade to a switch? How long?

This is a loaded question.   From what IOS to what IOS?  This is very important because you need to consider if the stack will need to load a new bootstrap firmware or not. 

There is also in issue about how big is your stack or how many switches in a stack.  

Ideally, if no bootstrap is involved, then it'll take about 7 minutes to reboot an entire stack of 6 switches.   I won't make a guess as to how long it'll take to boot 7 or more because I don't and will never have a switch stack of 7 and more.

[Charles Hill]

Hey Leo,

We downgraded several stacks, which included 2 to 5 switches per stack and each downgrade took between 30 to 40 minutes.  The downgrade was from c3750e-universalk9npe-mz.152-1.E  to c3750e-universalk9npe-mz.122-55.SE8.bin.

Is 30 to 40 minutes downtime about what you would expect.  I wasn't expecting that amount of downtime, but luckily I started with a stack where no one was affected.

Thanks.

[Leo Laohoo]

We downgraded several stacks, which included 2 to 5 switches per stack and each downgrade took between 30 to 40 minutes.  The downgrade was from c3750e-universalk9npe-mz.152-1.E  to c3750e-universalk9npe-mz.122-55.SE8.bin.

Hi Charles, 

This is exactly what I expect to see if going to and from an IOS above/below 12.2(58)SE.  Normally, if you upgrade, as an example, from 12.2(44)SE to 12.2(55)SE you will get around 10 minutes.  The minute you upgrade to anything above 12.2(58)SE, there is a bootstrap loader that gets upgraded (whether you like it or not) and this takes a heart-stopping 40 to 45 minutes.  Same goes if you downgrade from an IOS higher than 12.2(58)SE and to an IOS below 12.2(58)SE the IOS will downgrade the bootsrap loader and this, again, takes about 40 to 45 minutes.

[Charles Hill]

Heart stopping is right.  I'm glad to know that is what is expected.

Thank you for replying back!

(+5 to Leo)

[fbarclay51130]

Just uploading the new software will incur no downtime.  However, when you are ready to swap to the new IOS you will need to reload the switch.

I always plan for 30 minutes of downtime when doing an IOS upgrade.

PS: One thing that has bit me in the past make sure you set the switch to boot with the new software with the "boot system" command in global config (ie boot system flash:c2900-universalk9-mz.SPA.152-4.M7.bin)

Good luck!

Fred

[rus-admin]

If firmware upgrade needed, then downtime to 30 minutes. If not needed, then 5-10.

[Jerry Paul]

Hi,

Downtime is different on different media types like server, direct cable, fast Ethernet or gigabit Ethernet.

Approx downtime will be 25 to 30 minutes.

Jerry Paul

www.thenetworkhardware.com

[Glenn Martin]

Moving to Enterprise Support Community