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File system verification

File system verification
5.2.8

This page will review some commands that can be used to verify the router file system. One of these is the show version command. The show version command can be used to check the current image and the total amount of flash. It also verifies two other items that relate to how the IOS is loaded. It identifies the source of the IOS image that the router used to boot and displays the configuration register. Check the boot field setting of the configuration register to determine the location from which the router will load the IOS. If these do not agree, there may be a corrupt or missing IOS image in flash or there may be boot system commands in the startup configuration.
The show flash command can also be used to verify the file system. This command is used to identify IOS images in flash and the amount of flash that is available. This command is often used to confirm that there is ample space to store a new IOS image.
As previously mentioned, the configuration file may contain boot system commands. These commands can be used to identify the source of the desired IOS boot image. Multiple boot system commands may be used to create a fallback sequence to discover and load an IOS. These boot system commands will be processed in the order of their appearance in the configuration file.
This page concludes this lesson. The next page will summarize the main points from this module.

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