If you plug in an usb stick with ext3 format (for example to run fonz funplug) the file system on the usb stick will be destroyed. This happens while booting or you plug in the stick while the 325 is running.
I have found the line 864 in the script usbmount which tries to mount a vfat (without success). If you remove the line everything is ok!
Please correct this in the next firmware!
A file system error occurs also, if the 325 does not find both disks while booting (using RAID0). At the next boot (with both disks) the Volume_1 is corrupt.