I have built a freenas box with 4x1Tb drives configured as a raid5 array. I have started the CIFs service and mounted the array. I can see the array from a vista box and can write small files to it.

When I try to write multiple files it seems to clog up, then says it can't see the source file. I cancel it but then I have to reboot the freenas box to access the raid array again.

Any ideas?