function of command "boot system flash:/filename"?

Unanswered Question
Jan 17th, 2008

I need to configure a rourter referring to a template file. the template has above commond. I'm not sure what's the purpose of this command, do I need to make sure this flash filename here is the same as the image name from "show version" command?

I checked anohter router in production, the filename in "boot system flash" and "show version" output is different. please advise. thanks.

I have this problem too.
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ankbhasi Thu, 01/17/2008 - 21:42

Hi Wayne,

boot system flash: sets the boot path for switch / routers. Basically it tells the router/switch where to pick the IOS image from while booting.

The filename should be same as it is in flash. You can issue a command "dir flash:" and whatever file name you see there it should match the file name in boot system command.



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wayne_fan Thu, 01/17/2008 - 21:46

ok, I see. so the filename from "boot system flash" and "show ver" must be the same? I logged on one of the company routers and found they are different, will this be a problem?

ankbhasi Thu, 01/17/2008 - 21:52

Hi Wayne,

If there is a image mismatch name what you configure in boot system command and what exactly it is in flash, router/switch may boot in rommon or can also cause a booting loop.

I will say issue a "show version" and then issue a command "dir flash:" and then if you see the imge names are same in sh version and dir flash: output you can configure the same name in boot system command.



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mahmoodmkl Thu, 01/17/2008 - 21:45


The show version command will give two images.

The one will be the current image and the other will be the rommon boot image,so u need to go for the most recent verion of the image as the boot statement in u r config.



Richard Burts Fri, 01/18/2008 - 14:44


As Mahmood points out there will be 2 image names found in the output of show version. The first line of output of show version will include some version information and that usually will help clear up any confusion about which image is actually running.

If the router is running the boot image then probably there is a problem since the boot image does not contain full functionality.

If the router is not running the boot image then it should be running a regular image from flash. There is still a possibility that the image name in the boot system command will be different from the image that the router is running. If there is a boot system command (which is optional) the router will attempt to boot that image. But if it can not boot the image from the boot system command for some reason (I have seen spelling errors or perhaps the content of flash was updated with a different image but the boot system command was not updated) the router will generally look for an image in flash and if it finds one will boot the image that it finds.

A running image different from the image in the boot system command is not necessarily a problem. It is difficult to say in general whether there is a problem when the image that is running is different from the image name in the boot system command. The boot system command shows an intent to boot a certain image and if that image was not booted then the intent was not achieved. But that does not necessarily create a problem. The router may be running just fine on the image that it loaded even if it was different from the boot system command. The image running may be newer or may be older than the image in the boot system command or it might be a different feature set. You would need to consider these various factors to determine whether it was a problem or not.



glen.grant Fri, 01/18/2008 - 15:28

the best way to do this is to just do a "dir flash: and then copy and paste the image name from there into your boot statement , that way you can't fat finger the typing of the imagename .


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