Patent ID: 8643888

Claim:
An image forming apparatus comprising: at least three storing devices which are hard disk drives or solid state drives; a detecting unit to detect a failure of one of the storing devices or to expect an occurrence of the failure of one of the storing devices; and a control unit to control a storage of data in the storing devices, wherein in each of all of the storing devices, a first storing area for storing the data in a division storing method in which the data is divided into blocks and the blocks are dispersively stored in all of the storing devices, is secured, in each of at least two of the storing devices except at least one storing device, a second storing area for storing the data in a redundant storing method in which the data is redundantly stored in the two of the storing devices, is secured, and the control unit stops the storing device in which the failure is detected or the occurrence of the failure is expected by the detection unit, after the storing device is stopped, the control unit carries out the storage of the data in the division storing method by using all of the storing devices except the stopped storing device, in case that the stopped storing device is a storing device for storing the data in the redundant storing method, the control unit secures the second storing area in the one storing device which is not the stopped storing device and in which the data is not stored in the redundant storing method, the control unit copies the data stored in the second storing area of the storing device which is not the stopped storing device and in which the data is stored in the redundant storing method, to the secured second storing area of the one storing device, and after the data is copied, the control unit carries out the storage of the data in the redundant storing method by using the secured second storing area of the one storing device and the second storing area of the storing device which is not the stopped storing device and in which the data is stored in the redundant storing method.