It is normal, if your disk is experiencing problems.
That icon means that the iPod software is performing internal diagnostics for file system integrity. Depending on the size of your iPod it may take from 15 to 30 minutes, but some have reported times in excess of 50 minutes.
If I were you I wouldn't reset it while it's doing that.
If however you notic it's taking too much time for your liking, just force reset it, plug it in, and wipe the iPod with the iPod Software Updater and re-copy your files. It sounds like a lenghy process but it's really only a few clicks and a bit of waiting for iTunes to copy...