Abstract:
An apparatus for housing a drawer-type storage unit including a storage unit that stores data and a case in which the storage unit is contained in a drawable manner includes a drawing-status determining unit that determines whether the case is drawn from the apparatus; and a fan controlling unit that controls a revolutions-per-minute of a fan provided in the apparatus based on a result of determination by the determining unit.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a technology for preventing an abrupt increase of a temperature in a case of a drawer-type storage-unit housing apparatus. 
   2. Description of the Related Art 
   In a redundant-arrays-of-independent-disks (RAID) system, a plurality of hard disks is stored in a case, so that the hard disks can be managed efficiently, and space required for installing the RAID system is saved. The RAID system typically employs a drawer-type case that can be drawn open, so that the hard disks can be inspected or exchanged without difficulty. 
   However, the temperature within the case is increased by the hard disks. The hard disks can be harmed by excessively high temperature. One approach is to provide a cooling fan in the case to prevent the temperature from rising, as disclosed in Japanese Patent No. 3531662. 
   However, when the case is drawn open, the temperature within the case rises sharply due to the external temperature. 
   The case is left open for a considerable length of time because an administrator of the RAID system needs to inspect/exchange the hard disks with care, in consideration of safety and reliability. As a result, the temperature within the case rises excessively, which leads to an adverse impact on components inside the case. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to at least solve the problems in the conventional technology. 
   An apparatus according to one aspect of the present invention, which is for housing a drawer-type storage unit including a storage unit that stores data and a case in which the storage unit is contained in a drawable manner, includes a drawing-status determining unit that determines whether the case is drawn from the apparatus; and a fan controlling unit that controls a revolutions-per-minute of a fan provided in the apparatus based on a result of determination by the determining unit. 
   A method according to another aspect of the present invention, which is for controlling an apparatus for housing a drawer-type storage unit including a storage unit that stores data and a case in which the storage unit is contained in a drawable manner, includes determining whether the case is drawn from the apparatus; and controlling a revolutions-per-minute of a fan provided in the apparatus based on a result of determination at the determining. 
   The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a functional block diagram of a drawer-type hard-disk housing apparatus according to an embodiment of the present invention; 
       FIG. 2  is a functional block diagram of a HDD storing device shown in  FIG. 1 ; 
       FIG. 3  is a perspective view of a frame format of the HDD storing device; and 
       FIG. 4  is a flowchart of a processing performed by the HDD storing device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Exemplary embodiments of the present invention will be described below with reference to accompanying drawings. The present invention is not limited to these embodiments. 
   A concept of a drawer-type storage-unit housing apparatus (hereinafter, “drawer-type hard-disk housing apparatus”) according to an embodiment of the present invention is described below. When a user draws open a case storing hard disks from the drawer-type hard-disk housing apparatus, a fan provided inside the case is rotated at high-speed, so as to prevent a temperature increase within the case. 
   When the temperature inside the case is decreased by the fan, the rotational speed of the fan is reduced. Thus, power consumption is saved, and noise emitted from an accelerated fan is suppressed. 
     FIG. 1  is a functional block diagram of a drawer-type hard-disk housing apparatus  600  according to the present embodiment. The drawer-type hard-disk housing apparatus  600  includes hard disk drive (HDD) storing devices  100   a  to  100   h , a power supply unit  200 , HDD control units  300   a ,  300   b , an interface unit  400 , and a fan  500 . The left diagram is a front view, and the right diagram is a back view of the drawer-type hard-disk housing apparatus  600 . 
   Each of the HDD storing devices  100   a  to  100   h  stores a plurality of hard disks, and includes a cooling fan. When a user draws open any of the HDD storing devices  100   a  to  100   h , the fan is rotated to prevent a temperature increase. 
   Furthermore, when any of the HDD storing devices  100   a  to  100   h  is drawn open, the surrounding HDD storing devices are prevented from being drawn open. For example, when the HDD storing device  100   b  is drawn open, the HDD storing devices  100   a ,  100   f , and  100   c  are locked. Thus, a temperature increase in a surrounding HDD storing device is efficiently prevented. 
   The power supply unit  200  supplies power to the HDD storing devices  100   a  to  100   h , the HDD control units  300   a ,  300   b , the interface unit  400 , and the fan  500 . 
   The HDD control unit  300   a  manages the HDD storing devices  100   a  to  100   h , and requests the HDD storing devices  100   a  to  100   h  to write/read data. Furthermore, when any of the HDD storing devices  100   a  to  100   h  is drawn open, the HDD control unit  300   a  restricts the amount of data being transferred to the HDD storing device drawn open. This prevents a temperature increase of the hard disks stored inside the HDD storing device drawn open. 
   The HDD control unit  300   b  manages the HDD storing devices  100   a  to  100   h  when the HDD control unit  300   a  fails. 
   The interface unit  400  uses a specific communication protocol to communicate with other server devices, and the fan  500  cools the power supply unit  200 . 
     FIG. 2  is a functional block diagram of the HDD storing device  100   a . Descriptions of the HDD storing devices  100   b  to  100   e  are omitted because they have the same configuration as the HDD storing device  100   a . The HDD storing device  100   a  includes fans  110   a ,  110   b , hard disks  120 , a buffer  130 , a power supply unit  140 , a managing section  150 , a temperature sensor  160 , a drawer open sensor  170 , and a draw-open restriction unit  180 . 
   The fans  110   a ,  110   b  are used to cool the inside of the HDD storing device  100   a . The rotational speed of the fans  110   a ,  110   b  is changed according to an instruction from the managing section  150 . The hard disks  120  include a plurality of hard disks storing data acquired from the buffer  130 . 
   The buffer  130  temporarily stores data acquired from the managing section  150 , and passes the data to the hard disks  120 . Furthermore, the buffer  130  temporarily stores data acquired from the hard disks  120 , and passes the data to the managing section  150 . 
   The power supply unit  140  supplies power to the fans  110   a ,  110   b , the hard disks  120 , the buffer  130 , and the managing section  150 . 
   The managing section  150  manages the fans  110   a ,  110   b , and the hard disks  120 . The managing section  150  includes a fan managing unit  150   a , an interface unit  150   b , a data-transfer managing unit  150   c , and a drawer managing unit  150   d.    
   The fan managing unit  150   a  manages the rotational speed and rotational directions of the fans  110   a ,  110   b , based on information acquired by the temperature sensor  160  and the drawer open sensor  170 . The temperature sensor  160  detects the temperature within the HDD storing device  100   a , and passes the data of the detected temperature (hereinafter, “temperature data”) to the fan managing unit  150   a  and the data-transfer managing unit  150   c . The HDD storing device  100   a  consists of a main unit and a drawer unit that is drawn open from the main unit. The drawer unit stores the fans  110   a ,  110   b , the hard disks  120 , the buffer  130 , the power supply unit  140 , the managing section  150 , the temperature sensor  160 , the drawer open sensor  170 , and the draw-open restriction unit  180 . When the drawer unit is drawn open from the main unit, the drawer open sensor  170  notifies this to the fan managing unit  150   a.    
   When a notification that the drawer unit is drawn open is received, the fan managing unit  150   a  increases the rotational speed of the fans  110   a ,  110   b . Furthermore, the fan managing unit  150   a  controls the rotational directions of the fans  110   a ,  110   b  so as to make air flow into the drawer unit from outside. 
   When the drawer unit is drawn open, the top part of the drawer unit is uncovered. Accordingly, air from the fan  110   a  and air from the fan  110   b  clash into each other. As a result, heat of the hard disks  120  is efficiently discharged outside the HDD storing device  100   a , enhancing a cooling effect. 
   Furthermore, when temperature data acquired from the temperature sensor  160  is below a predetermined level, the fan managing unit  150   a  reduces the rotational speed of the fans  110   a ,  110   b  to a regular speed. 
   When the drawer unit of the HDD storing device  100   a  is drawn open, the fan managing unit  150   a  increases the rotational speed of the fans  110   a ,  110   b . When the temperature within the HDD storing device  100   a  is sufficiently decreased by the cooling effect of the accelerated fans  110   a ,  110   b , the fan managing unit  150   a  reduces the rotational speed of the fans  110   a ,  110   b  to a regular speed. Thus, power consumption can be saved, and noise emitted from the fans  110   a ,  110   b  can be suppressed. When the temperature within the HDD storing device  100   a  exceeds a predetermined level, the fan managing unit  150   a  accelerates the fans  110   a ,  110   b  again. 
   When the fan managing unit  150   a  receives a notification that a drawer unit of any of the surrounding HDD storing devices is drawn open, the fan managing unit  150   a  accelerates the fans  110   a ,  110   b . This minimizes a temperature increase within the HDD storing device  100   a  caused by the external temperature. 
   The interface unit  150   b  uses a specific communication protocol to communicate with the HDD control units  300   a ,  300   b , and the HDD storing devices  100   b  to  100   h.    
   The data-transfer managing unit  150   c  acquires data from the interface unit  150   b , and transfers the data to the hard disks  120  though the buffer  130 . The data-transfer managing unit  150   c  transfers data temporarily stored in the buffer  130  to the interface unit  150   b.    
   When the data-transfer managing unit  150   c  receives from the drawer managing unit  150   d  a notification that the drawer unit of the HDD storing device  100   a  is drawn open, the data-transfer managing unit  150   c  restricts the amount of data being transferred from the buffer  130  to the hard disks  120 . This prevents the temperature of the hard disks  120  from increasing. 
   The data-transfer managing unit  150   c  acquires temperature data from the temperature sensor  160 , and determines whether the temperature within the HDD storing device  100   a  exceeds a predetermined level. When the temperature exceeds the predetermined level, the data-transfer managing unit  150   c  restricts the amount of data being transferred from the buffer  130  to the hard disks  120 . 
   When the temperature falls below the predetermined level, the data-transfer managing unit  150   c  releases the restriction on the amount data being transferred from the buffer  130  to the hard disks  120 . 
   When the drawer managing unit  150   d  receives from the drawer open sensor  170  a notification that the drawer unit of the HDD storing device  100   a  is drawn open, the drawer managing unit  150   d  transfers the notification to the fan managing unit  150   a , the data-transfer managing unit  150   c , the HDD storing devices  100   b  to  100   h , and the HDD control units  300   a ,  300   b.    
   When the HDD control units  300   a ,  300   b  receives from the drawer managing unit  150   d  the notification that the drawer unit is drawn open, the amount of data transferred from the HDD control units  300   a ,  300   b  to the HDD storing device  100   a  is restricted. Thus, a temperature increase within the HDD storing device  100   a  is prevented. 
   When the drawer managing unit  150   d  receives a notification that any of the HDD storing devices  100   b  to  100   h  is drawn open, the drawer managing unit  150   d  instructs the draw-open restriction unit  180  to lock the drawer unit of the HDD storing device  100   a  so that is not drawn open from the main unit. Thus, the temperature within the HDD storing device  100   a  is unaffected. 
     FIG. 3  is a perspective view of a frame format of the HDD storing device  100   a . The HDD storing device  100   a  includes a fan unit (corresponding to the fan  110   a  shown in  FIG. 2 ), an HDD (corresponding to the hard disks  120  shown in  FIG. 2 ), a port bypass controller (PBC) (corresponding to the managing section  150  shown in  FIG. 2 ), a buffer pool (BP) (corresponding to the buffer  130  shown in  FIG. 2 ), and so forth. 
     FIG. 4  is a flowchart of a processing performed by the HDD storing device  100   a . When the drawer unit of the HDD storing device  100   a  is drawn open, the drawer open sensor  170  sends a notification to the fan managing unit  150   a  and the drawer managing unit  150   d  that the drawer unit of the HDD storing device  100   a  is drawn open (step S 101 ), and the fan managing unit  150   a  increases the rotational speed of the fans  110   a ,  110   b  (step S 102 ). 
   The drawer managing unit  150   d  sends a notification to the data-transfer managing unit  150   c  that the drawer unit is drawn open, and the data-transfer managing unit  150   c  restricts the amount of data being transferred from the buffer  130  to the hard disks  120  (step S 103 ). 
   The fan managing unit  150   a  and the data-transfer managing unit  150   c  acquires temperature data from the temperature sensor  160  (step S 104 ). Based on the temperature acquired, the fan managing unit  150   a  changes (or maintains) the rotational speed of the fans  110   a ,  110   b , and the data-transfer managing unit  150   c  changes (or maintains) the amount of data being transferred from the buffer  130  to the hard disks  120  (step S 105 ), and the system control returns to step S 104 . 
   In the drawer-type hard-disk housing apparatus  600  according to the present embodiment, when the drawer open sensor  170  detects that the drawer unit of the HDD storing device  100   a  is drawn open, the drawer open sensor  170  notifies this to the fan managing unit  150   a , and the fan managing unit  150   a  increases the rotational speed of the fans  110   a ,  110   b . Moreover, when the drawer unit is drawn open, the data-transfer managing unit  150   c  restricts the amount of data being transferred from the buffer  130  to the hard disks  120 , so that the temperature within the HDD storing device  100   a  is efficiently prevented from increasing. The same applies to any of the HDD storing devices  100   b  to  100   h.    
   According to the present invention, the temperature within a case is prevented from increasing. 
   Furthermore, according to the present invention, the temperature of hard disks is prevented from rising. 
   Moreover, according to the present invention, power consumption is saved, and noise emitted from a fan is suppressed. 
   Although the invention has been described with respect to a specific embodiment for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.