You anyway need to take a downtime, atleast 5-10 mins for this upload... archiving the software into the box, will not affect performance for the users, but once the IOS is uploaded onto the box, it does not directly take the OS as boot image.. you anyway need to reload the 3750's to activate the IOS images... i wouldnt say this as a big hit, but you can schedule and do this change !!!!
I'm attaching a very good doc, which will guide you through this upgrade.
Upgrading the 3750 Stack is relatively easy. You just copy from tftp then to Flash1: do the same but from tftp to flash2: (Second switch) Once done isssue the reload command on the master. The master will reaload the whole switch stack.
Delete the old IOS before your reboot otherwise you have to specify which IOS the switch should reboot from.
I found it easier to use Cisco Network Assistant to upgrade a software on IOS switches. You can build a cluster out of stacked switches, and then you can pick two or more switches at one to upgrade. TFTP upload takes much longer, but it works fine. In addition, CNA takes car about all upgrade changes (i.e. specifying correct "boot system" sequence).
Thanks all, I might not have been clear enough in my first post; upgrading the software isn't the issue (we'll push the ios out with cisco works ahead of time so its ready to go); we were just looking for a way that the stack could be reloaded in a way that some of it would always be up. We have many critical devices attached to multiple stacks, most ether-channeled across the switches for maximum redundancy (so we can lose a switch, or a core switch behind them, and not take a hit to our end devices), but obviously upgrading software is going to cause a hit. Didn't think there was a way around it, but wanted to make sure.
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
interface we use the VLAN tag to demultiplex the VLANs. The switch needs
to determine which MAC Address table to look in for a forwarding
decision. To do this we require the switch to do...
[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
Sup32 that allows one to capture packets on the RP or SP inband. The
netdr command can be used to capture both Tx and Rx packets in the
software switching path. This is not a substitut...
IntroductionOSPF, being a link-state protocol, allows for every router
in the network to know of every link and OSPF speaker in the entire
network. From this picture each router independently runs the Shortest
Path First (SPF) algorithm to determine the b...