I'm getting lots of smartd messages in my log file, e.g. Device: /dev/sda, 2 Currently unreadable?

them be holes in your drive that can not be read or are hidden files or protected content this doesn't mean that there is a prob this is just a bit it have to p over to read another bit or write another bit some info CANNOT BE MOVED !!! defrag the drive and this will show your your drive life span ise first !!!!