fsck on USB attached drives

Netgear recommends EXT4 format for USB-attached drives used for backup of a ReadyNAS.  Of course, USB drives have the same vulnerability as the drives in the NAS.  When the USB drive is NTFS format, one can do chkdsk in Windows by plugging the drive into a Win PC.  However, this is not so easy if the USB drive is EXT4 format.  Options as pointed out by StephenB are to SSH into the NAS and run the command line there, or to setup linux in a Windows VM and use the command line fsck there. 

Request: include a fsck equivalent function in the OS6 interface.  Ideally, it should allow scheduling (take disk off line, do file check, return to online status).  However, I would be happy if it was user selectable without the scheduling feature.