Core issue
The time to boot up depends on the modules you have, your configuration, your diagnostic level previously set, problems with Flash memory, and the new features included in every version. A normal boot-up time can be around 5 minutes.
Resolution
If you have the diagnostic level in the complete mode, then this level runs all possible POST tests every time you boot up the switch. This can take several seconds. If you have a fully populated chassis (which you have), this can cause the boot process to take several minutes. In Catalyst OS (CatOS), use the set test diaglevel command to change the diagnostic level to minimum. Alternatively, you can bypass diagnostics for testing purposes. The default is minimal diagnostics.
In IOS , use the diagnostic bootup level command to set the bootup diagnostic level.
If the issue is related to memory then format the Flash memory in order to reduce the delay in booting. Use the format command.
Open a case with Cisco Technical Support for further assistance and support.
