I've been messing around with my storage array (in that case 2xMD3000 SAS) and between the scans/rescans/delete/add my /dev/sdx block devices are all messed up. Some of them are non existent and using fdisk on them gives:
fdisk: unable to open sdc: No such device or address
It's not a real problem as I'm using
/dev/disk/by-id/wwn-xxxxx anyway, but I would like to know if there is a way to trigger the kernel into updating/removing those empty and broken devices somehow.