A storage device controlling apparatus includes: a plurality of channel
controllers having a circuit board on which are formed a file access
processing section receiving requests to input and output data in files
as units from an information processing apparatus and an I/O processor
outputting I/O requests corresponding to the requests to input and output
data to a storage device; and a disk controller executing input and
output of data into and from the storage device in response to the I/O
requests sent from the I/O processors. In the storage device controlling
apparatus, the disk controller performs a replication management
processing whereby data is also written into a second logical volume to
store a copy of the data in the second logical volume, when the data is
written into a first logical volume.