Comment 3 for bug 507493

This is perfectly safe and nothing to worry about, just annoying.

Each volume needs to be checked for errors every x mountings, but with live scripts (live-initramfs for Puredyne, and casper for Ubuntu 10.10), when the system boots it looks if there are any persistent volumes or files to load the customized user settings. This can be done up to four times for each volume, meaning that always booting on a live system will make have your disks checks up to four time more than usual.

The only workaround is to pass as boot argument where the persistent file/volume is or remove the persistent boot argument for no checks at all (in which case you won't have your settings saved in between reboots).