# Patent

## Title
Computer device and cluster server device

## Abstract

A computer device includes a plurality of information processing units configured to execute respective information processing functions, a plurality of storage units, one of which is arranged in each of the information processing units, and which are removable, a plurality of storage devices physically dispersed in the storage units, and having a redundant configuration, where one storage unit includes at least two storage devices, and a plurality of controllers configured to be installed in the information processing units, and to access the storage devices, where each information processing unit includes one of the controllers.

## Background
This application is a continuing application, filed under 35 U.S.C. §111(a), of International Application PCT/JP2003/010343, filed Aug. 14, 2003.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a computer device and a cluster server device that can hot-swap a storage device having a redundant configuration, in a plurality of information processing units.
2. Description of the Related Art
FIG. 9 is a perspective view of an external configuration of a conventional computer device 10. The computer device 10 is, for example, a server device including a central processing unit (CPU) (not shown), a hard disk controller (HDD), and the like, provided inside a casing 11.
Two slots 121 and 122 are formed in a front face of the casing 11. Hard disks (HDD) 131 and 132 are removably inserted into the slots 121 and 122.
The HDD controller controls writing to and reading from the HDDs 131 and 132, which are large-capacity storage devices that store various types of data handled by the CPU. The HDDs 131 and 132 are arranged in a redundant configuration.
A mirror ring is used to store identical data in the HDDS 131 and 132, so that one can be used for recovery if the other breaks down.
The computer device 10 also includes a function of, when one of the HDDs 131 and 132 breaks down, replacing the broken HDD without terminating the operation of the computer device 10 (hot-swap).
If the HDD 131 breaks down, data is recovered from the HDD 132. The broken HDD 131 is removed from the slot 121 without terminating the operation of the computer device 10, and a replacement HDD (not shown) is inserted into the slot 121.
Japanese Patent Application Laid-Open No. H11-184643 discloses a conventional computer device. FIG. 10 is a perspective view of an external configuration of a conventional computer device 20. The computer device 20 is a cluster server device (blade server device) in which a plurality of card-type information processing units 301 to 30n can be inserted into a casing 21. Each of the information processing units 301 to 30n has the same functions as the computer device 10 (see FIG. 9).
‘n’ number of slots 221 to 22n are formed in a front face of the casing 21. The information processing units 301 to 30n are removably inserted into the slots 221 to 22n.
FIG. 11 is a cross section taken along line X-X′ of FIG. 10. In FIG. 11, like reference numerals designate like parts as those shown in FIG. 10. In FIG. 11, a back plane 23 is provided inside the casing 21, and is physically and electrically connected to the information processing units 301 to 30n (see FIG. 10). The back plane 23 supplies electrical power to the information processing units 301 to 30n, and has a function of providing an interface.
The information processing unit 301 consists of a card-shaped printed circuit board 311, an HDD 32A1, an HDD 32B1, a CPU 331, and an HDD controller 341, and includes the same server functions as the computer device 10, as mentioned already.
The HDD 32A1, the HDD 32B1, the CPU 331, and the HDD controller 341 are mounted on the printed circuit board 311. The information processing unit 301 is mounted on the back plane 23 via a connector 351.
The HDD controller 341 controls writing to and reading from the HDD 32A1 and the HDD 32B1, which are large-capacity storage devices that store various types of data handled by the CPU 331. The HDD 32A1 and the HDD 32B1 are arranged in a redundant configuration.
A mirror ring is used to store identical data in the HDDs 32A1 and 32B1, so that one can be used for recovery if the other breaks down. Therefore, if the HDD 32A1 breaks down, data is recovered from the HDD 32B1.
In the conventional computer device 20 (FIGS. 10 and 11), the HDD 32A1 and the HDD 32B1 in the information processing unit 301 shown in FIG. 11 have a redundant configuration. However, although data can be recovered from one of the HDDs if the other breaks down, there is a problem that the broken HDD cannot be hot-swapped.
The HDD 32A1 and the HDD 32B1 are mounted on the same printed circuit board 311, and to replace the broken HDD 32A1, the entire printed circuit board 311 must be removed from the back plane 23, and the operation of the information processing unit 301 (server) must be terminated while the broken HDD 32A1 is replaced with a replacement HDD. The information processing unit 301 must then be remounted on the back plane 23.
SUMMARY OF THE INVENTION
It is an object of the present invention to at least solve the problems in the conventional technology.
According to an aspect of the present invention, a computer device includes a plurality of information processing units configured to execute respective information processing functions; a plurality of storage devices configured to be mounted in the information processing units in a physically dispersed manner, and configured to have a redundant configuration; and a controller configured to access the storage devices.
According to another aspect of the present invention, a computer device includes a plurality of information processing units configured to execute respective information processing functions; a plurality of storage units configured to form a part of the information processing units, and configured to be removably mounted therein; a plurality of storage devices configured to be mounted in the storage units in a physically dispersed manner, and configured to have a redundant configuration, where one storage unit includes at least two storage devices; and a plurality of controllers configured to be mounted in the information processing units and to access the storage devices, where each information processing unit includes one of the controllers. According to still another aspect of the present invention, a cluster server device includes a plurality of information processing units, each including a server function; a plurality of storage devices configured to be mounted in the information processing units in a physically dispersed manner, and configured to have a redundant configuration; and a controller configured to access the storage devices.
According to still another aspect of the present invention, a cluster server device includes a plurality of information processing units, each including a server function; a plurality of storage units configured to form a part of the information processing units, and configured to be removably mounted therein; a plurality of storage devices configured to be mounted in the storage units in a physically dispersed manner, and configured to have a redundant configuration; and a plurality of controllers configured to be respectively mounted in the information processing units, and to access the storage devices, where each information processing unit includes one of the controllers.
The above 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 schematic plan view of a configuration of a computer device according to a first embodiment of the present invention;
FIG. 2 is a cross section taken along line Y-Y′ of FIG. 1;
FIG. 3 is a diagram to explain a hot-swap method according to the first embodiment;
FIG. 4 is another diagram to explain the hot-swap method according to the first embodiment;
FIG. 5 is still another diagram to explain the hot-swap method according to the first embodiment;
FIG. 6 is a schematic plan view of a configuration of a computer device according to a second embodiment;
FIG. 7 is a diagram to explain a hot-swap method according to the second embodiment;
FIG. 8 is another diagram to explain the hot-swap method according to the second embodiment;
FIG. 9 is a perspective view of an external configuration of a conventional computer device;
FIG. 10 is a perspective view of the external configuration of a conventional computer device; and
FIG. 11 is a cross section taken along line X-X′ of FIG. 10.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Exemplary embodiments of the present invention will be explained in detail below with reference to the accompanying drawings.
FIG. 1 is a schematic plan view of a configuration of a computer device according to a first embodiment of the present invention. FIG. 2 is a cross section taken along line Y-Y′ of FIG. 1. In FIGS. 1 and 2, like reference numerals designate like parts as those shown in FIGS. 10 and 11.
A computer device 40 shown in FIG. 1 is a cluster server device (blade server device) in which a plurality of information processing units 501, 502, 503, . . . can be provided in the casing 21.
In FIG. 1, although the information processing units 501, 502, 503, . . . are provided vertically in the same manner as the information processing units 301, 302, . . . shown in FIG. 10, they are depicted in a plan view in the drawing.
The information processing units 501, 502, 503, . . . can be freely inserted into and removed from slots 221, 222, 223, . . . in the casing 21.
A back plane 41 is provided inside the casing 21, and is physically and electrically connected to the information processing units 501, 502, . . . via connectors 571, 572, . . . (see FIG. 2). The back plane 41 supplies electrical power to the information processing units 501, 502, 503, . . . , and provides an interface.
Each of the information processing units 501, 502, 503, . . . includes a server function similar to that of the computer device 10 (see FIG. 9).
Two of the information processing units 501, 502, 503, . . . form one set. In FIG. 1, the information processing units 501 and 502 form one set.
The information processing unit 501 includes a storage unit 511 and a processor unit 541. The storage unit 511 and the processor unit 541 can be freely mounted and removed via a connector 531. The storage unit 511 includes an HDD 52A1 and an HDD 52B1 that are mounted on the same circuit board. The processor unit 541 includes a CPU 55A1 and an HDD controller 56A1 that are mounted on the same circuit board.
The information processing unit 502 includes a storage unit 512 and a processor unit 542. The storage unit 512 and the processor unit 542 can be freely mounted and removed via a connector 532. The storage unit 512 includes an HDD 52A2 and an HDD 52B2 that are mounted on the same circuit board. The processor unit 542 includes a CPU 55B2 and an HDD controller 56B2 that are mounted on the same circuit board.
In the information processing units 501 and 502, components represented by (A) in FIG. 1 (the HDD 52A1, the HDD 52A2, the CPU 55A1, and the HDD controller 56A1) form a group A. This group A corresponds to one computer device 10 (see FIG. 9) having a redundant configuration consisting of two HDDs.
In group A, the HDD controller 56A1 controls writing to and reading from the HDD 52A1 and the HDD 52A2, which are large-capacity storage devices that store various types of data handled by the CPU 55A1.
The HDD 52A1 is connected to the HDD controller 56A1 via the connector 531. The HDD 52A2 is connected to the HDD controller 56A1 via the connector 531, the processor unit 542, the connector 572, the back plane 41, and the connector 571.
The HDD 52A1 and the HDD 52A2 are mounted by dispersion in physically separate storage units (the storage units 511 and 512).
Components represented by (B) in FIG. 1 (the HDD 52B1, the HDD 52B2, the CPU 55B2, and the HDD controller 56B2) form a group B. This group B corresponds to one computer device 10 (see FIG. 9) having a redundant configuration consisting of two HDDs.
In group B, the HDD controller 56B2 controls writing to and reading from the HDD 52B1 and the HDD 52B2, which are large-capacity storage devices that store various types of data handled by the CPU 55B2.
The HDD 52B1 is connected to the HDD controller 56B2 via the connector 531, the processor unit 541, the connector 571, the back plane 41, and the connector 572. The HDD 52B2 is connected to the HDD controller 56B2 via the connector 532.
The HDD 52B1 and the HDD 52B2 are mounted by dispersion in physically separate storage units (the storage units 511 and 512).
A hot-swap method according to the first embodiment will be explained with reference to FIGS. 3 to 5. An example in which the HDD 52A2 breaks down and is hot-swapped without terminating the operation of the information processing units 501 and 502 will be explained with reference to FIG. 3.
In FIG. 3, when the HDD 52A2 of the storage unit 512 in group A breaks down, data is recovered from the other HDD 52A1 having the redundant configuration, thereby enabling continuous operation.
Due to the breakdown of the HDD 52A2, the redundant configuration cannot be utilized in group A, and therefore the HDD 52A2 is hot-swapped. As shown in FIG. 4, the storage unit 512 is removed as a whole and separated from the processor unit 542.
In group A, the HDD 52A1 is currently used and is accessed by the CPU 55A1 and the HDD controller 56A1, whereby operation continues without being affected by the hot-swap.
Similarly in group B, the HDD 52B1 is currently used and is accessed by the CPU 55B2 and the HDD controller 56B2, whereby operation continues without being affected by the hot-swap.
In the disconnected storage unit 512, the broken HDD 52A2 is replaced with a replacement HDD 52A2′.
As shown in FIG. 5, after this replacement, the storage unit 512 is mounted on the processor unit 542 via the connector 532. This restores the computer device 40 to its original state before breakdown.
As described above, according to the first embodiment, the HDDs 52A1 and 52A2 (storage devices) having a redundant configuration are mounted by physical dispersion, in a plurality of freely removable storage units 511 and 512 that form a part of the information processing units 501 and 502. Therefore, even if one HDD 52A2 breaks down and the storage unit 512 is removed, the HDD controller 56A1 can access the HDD 52A1 provided in the other storage unit 511, so the HDDs having the redundant configuration can be hot-swapped in the information processing units 501 and 502.
While the first embodiment describes an example in which an HDD can be hot-swapped when there are two information processing units (information processing units 501 and 502) in one set, it is also possible to hot-swap an HDD when one set consists of three (or four or more) information processing units. An example of such a configuration is described below as a second embodiment.
FIG. 6 is a schematic plan view of the configuration of a computer device according to the second embodiment of the present invention. In FIG. 6, like reference numerals designate like parts as those shown in FIG. 1.
A computer device 60 shown in FIG. 6 is a cluster server device (blade server device) in which a plurality of card-shaped information processing units 701, 702, 703, . . . can be mounted in the casing 21.
The information processing units 701, 702, 703, . . . can be freely inserted into and removed from slots 221, 222, 223, . . . in the casing 21.
A back plane 78 is provided inside the casing 21, and is physically and electrically connected to the information processing units 701, 702, 703, . . . via connectors 771, 772, 773, . . . . The back plane 78 supplies electrical power to the information processing units 701, 702, 703, . . . and also provides an interface.
Each of the information processing units 701, 702, 703, . . . includes a server function similar to that of the computer device 10 (see FIG. 9).
Three of the information processing units 701, 702, 703, . . . form one set, as shown in FIG. 6.
The information processing unit 701 includes a storage unit 711 and a processor unit 741. The storage unit 711 and the processor unit 741 can be freely mounted and removed via a connector 731. The storage unit 711 includes an HDD 72A1, an HDD 72B1, and an HDD 72C1, which are mounted on the same circuit board. The processor unit 741 includes a CPU 75A1 and an HDD controller 76A1 that are mounted on the same circuit board.
The information processing unit 702 includes a storage unit 712 and a processor unit 742. The storage unit 712 and the processor unit 742 can be freely mounted and removed via a connector 732. The storage unit 712 includes an HDD 72A2, an HDD 72B2, and an HDD 72C2, which are mounted on the same circuit board. The processor unit 742 includes a CPU 75B2 and an HDD controller 76B2 that are mounted on the same circuit board.
The information processing unit 703 includes a storage unit 713 and a processor unit 743. The storage unit 713 and the processor unit 743 can be freely mounted and removed via a connector 733. The storage unit 713 includes an HDD 72A3, an HDD 72B3, and an HDD 72C3, which are mounted on the same circuit board. The processor unit 743 includes a CPU 75C3 and an HDD controller 76C3 that are mounted on the same circuit board.
In the information processing units 701, 702, and 703, components represented by (A) in FIG. 6 (the HDD 72A1, the HDD 72A2, HDD 72A3, the CPU 75A1, and the HDD controller 76A1) form a group A. This group A corresponds to one computer device 10 (see FIG. 9) having a redundant configuration consisting of three HDDs (n+1 redundant configuration).
In group A, the HDD controller 76A1 controls writing to and reading from the HDD 72A1, the HDD 72A2, and the HDD 72A3 which are large-capacity storage devices that store various types of data handled by the CPU 75A1.
The HDD 72A1 is connected to the HDD controller 76A1 via the connector 731. The HDD 72A2 is connected to the HDD controller 76A1 via the connector 732, the processor unit 742, the connector 772, the back plane 78, and the connector 771.
The HDD 72A3 is connected to the HDD controller 76A1 via the connector 733, the processor unit 743, the connector 773, the back plane 78, and the connector 771.
The HDDs 72A1, 72A2, and 72A3 are mounted by dispersion in physically separate storage units (the storage units 711, 712, and 713).
Similarly, components represented by (B) in FIG. 6 (the HDD 72B1, the HDD 72B2, the HDD 72B3, the CPU 75B2, and the HDD controller 76B2) form a group B. This group B corresponds to one computer device 10 (see FIG. 9) having a redundant configuration consisting of three HDDs (n+1 redundant configuration).
In group B, the HDD controller 76B2 controls writing to and reading from the HDD 72B1, the HDD 72B2, and the HDD 72B3, which are large-capacity storage devices that store various types of data handled by the CPU 75B2.
The HDD 72B1 is connected to the HDD controller 76B2 via the connector 731, the processor unit 741, the connector 771, the back plane 78, and the connector 772.
The HDD 72B2 is connected to the HDD controller 76B2 via the connector 732. The HDD 72B3 is connected to the HDD controller 76B2 via the connector 733, the processor unit 743, the connector 773, the back plane 78, and the connector 772.
The HDDs 72B1, 72B2, and 72B3 are mounted by dispersion in physically separate storage units (the storage units 711, 712, and 713).
Similarly, components represented by (C) in FIG. 6 (the HDD 72C1, the HDD 72C2, the HDD 72C3, the CPU 75C3, and the HDD controller 76C3) form a group C. This group C corresponds to one computer device 10 (see FIG. 9) having a redundant configuration consisting of three HDDs (n+1 redundant configuration).
In group C, the HDD controller 76C3 controls writing to and reading from the HDD 72C1, the HDD 72C2, and the HDD 72C3 which are large-capacity storage devices that store various types of data handled by the CPU 75C3.
The HDD 72C1 is connected to the HDD controller 76C3 via the connector 731, the processor unit 741, the connector 771, the back plane 78, and the connector 773.
The HDD 72C2 is connected to the HDD controller 76C3 via the connector 732, the processor unit 742, the connector 772, the back plane 78, and the connector 773. The HDD 72C3 is connected to the HDD controller 76C3 via the connector 733.
The HDDs 72C1, 72C2, and 72C3 are mounted by dispersion in physically separate storage units (the storage units 711, 712, and 713).
A hot-swap method according to the second embodiment will be explained with reference to FIGS. 6 to 8. An example in which the HDD 72A2 breaks down and is hot-swapped without terminating the operation of the information processing units 701, 702, and 703 as shown in FIG. 6 will be explained.
In FIG. 6, when the HDD 72A2 of the storage unit 712 in group A breaks down, data is recovered from another HDD 72A1 (or HDD 72A3) having the redundant configuration, thereby enabling continuous operation.
In group A, the HDD 72A2 is hot-swapped due to breakdown. As shown in FIG. 7, the storage unit 712 is removed as a whole and separated from the processor unit 742.
In group A, the HDD 72A1 (or HDD 72A3) is currently used and is accessed by the CPU 75A1 and the HDD controller 76A1, whereby operation continues without being affected by the hot-swap.
Similarly, in group B, the HDD 72B1 (or HDD 72B3) is currently used and is accessed by the CPU 75B2 and the HDD controller 76B2, whereby operation continues without being affected by the hot-swap.
Similarly, in group C, the HDD 72C1 (or HDD 72C3) is currently used and is accessed by the CPU 75C3 and the HDD controller 76C3, whereby operation continues without being affected by the hot-swap.
In the disconnected storage unit 712, the broken HDD 72A2 is replaced with a replacement HDD 72A2′.
As shown in FIG. 8, after this replacement, the storage unit 712 is mounted in the processor unit 742 via the connector 732. This restores the computer device 60 to its original state before breakdown.
As described above, the second embodiment achieves the same effects as the first embodiment.
Although the first and the second embodiments of the present invention have been explained in detail with reference to the accompanying drawings, specific configurational examples are not limited to the embodiments, and any design changes or the like to the embodiments are intended to be embraced in the present invention without departing from the scope of the invention.
As explained above, according to the present invention, a plurality of storage devices having a redundant configuration are mounted by physical dispersion in a plurality of information processing units. Therefore, even if an information processing unit is removed when one of its storage devices breaks down, a controller can access a storage device mounted in another information processing unit, and the storage device having the redundant configuration can be hot-swapped in the information processing units.
According to the present invention, a plurality of storage devices having a redundant configuration are mounted by physical dispersion in a plurality of freely removable storage units that form a part of a plurality of information processing units. Therefore, even if one of the storage devices breaks down and the storage unit is removed, a controller can access a storage device mounted in another storage unit, thereby enabling the storage device having the redundant configuration to be hot-swapped in the information processing units.
According to the present invention, a storage device having a redundant configuration can be hot-swapped in a server having a plurality of information processing units.
According to the present invention, a storage device can be hot-swapped in case of breakdown.
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.

## Claims

1. A computer device comprising:
a plurality of information processing units configured to execute respective information processing functions and each having at least one removable storage unit;
a plurality of storage devices physically dispersed in each of the at least one storage unit provided in the information processing units, said storage devices being capable of hot-swapping without terminating the operation of the information processing units, and having a redundant configuration, wherein each information processing unit includes at least two storage devices; and
a plurality of controllers configured to access the storage devices, wherein:
the information processing units are grouped into sets;
a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set; and
in each set, each of the controllers is mounted on each of the information processing units, and accesses only one of the plurality of storage devices within each of the information processing units included in the set.

2. The computer device according to claim 1, wherein
the storage devices are removable,
the information processing units include at least a first information processing unit and a second information processing unit, and
when a storage device in the first information processing unit is unusable, the controller uses a storage device in the second information processing unit.

3. The computer device according to claim 1, wherein the information processing unit functions as a server.

4. A computer device comprising:
a plurality of information processing units configured to execute respective information processing functions;
a plurality of storage units arranged in the information processing units, and that are removable, wherein one information processing unit includes one storage unit;
a plurality of storage devices physically dispersed in the storage units and having a redundant configuration, said storage devices being capable of hot-swapping without terminating the operation of the information processing units, wherein one storage unit includes at least two storage devices; and
a plurality of controllers configured to be installed in the information processing units and to access the storage devices, wherein each information processing unit includes one of the controllers,
wherein the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers.

5. The computer device according to claim 4, wherein
the storage devices are removable,
the information processing units include at least a first information processing unit and a second information processing unit, and
when a storage device in a first information processing unit is unusable, the controller in the first information processing unit uses a storage device in the second information processing unit.

6. The computer device according to claim 4, wherein the information processing unit functions as a server.

7. A cluster server device comprising:
a plurality of information processing units, each capable of functioning as a server and each having at least one removable storage unit;
a plurality of storage devices physically dispersed in each of the at least one storage unit provided in the information processing units, said storage devices being capable of hot-swapping without terminating the operation of the information processing units, and having a redundant configuration, wherein each information processing unit includes at least two storage devices; and
a plurality of controllers configured to access the storage devices,
wherein the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set, each of which is mounted on each of the information processing units, and accesses only one of the plurality of storage devices within each of the information processing units included in the set.

8. The cluster server device according to claim 7, wherein the information processing units include at least a first information processing unit and a second information processing unit, and
when one of the storage devices in the first information processing unit is unusable, the controller uses another one of the storage devices in the second information processing unit.

9. A cluster server device comprising:
a plurality of information processing units, each capable of functioning as a server;
a plurality of storage units arranged in the information processing units, and that are removable, wherein one information processing unit includes one storage unit;
a plurality of storage devices physically dispersed in the storage units, said storage devices being capable of hot-swapping without terminating the operation of the information processing units, and having a redundant configuration, wherein one storage unit includes at least two storage devices; and
a plurality of controllers configured to be installed in the information processing units, and to access the storage devices, wherein each information processing unit includes one of the controllers,
wherein the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers.

10. The cluster server device according to claim 9, wherein
the storage devices are removable,
the information processing units include at least a first information processing unit and a second information processing unit, and
when a storage device in a first information processing unit is unusable, the controller in the first information processing unit uses a storage device in the second information processing unit.

11. An information processing device comprising:
a plurality of processing units each including a processor, a storage controller, and at least one removable storage unit, wherein the at least one removable storage unit is detachably connected to the processing unit, and includes a plurality of storage devices, said storage devices having redundant configuration and being capable of hot-swapping without terminating the operation of the information processing unit; and
a back plane to which each of the processing units is detachably connected, wherein
the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set, each of which is mounted on each of the information processing units, and accesses only one of the plurality of storage devices within each of the information processing units included in the set.

12. A computer device, comprising:
a backplane unit; and
a plurality of information processing units each connected to the backplane unit, each of the information processing units, including:
a processor unit,
a storage unit attached to the processor unit in a removable manner,
a plurality of storage devices contained in the storage unit, and
a controller mounted on the processor unit that is connected to and controls access to at least one of the storage devices in a storage unit attached to the processor unit in which the controller is mounted, and to at least one of the storage devices in a storage unit attached to the other processing unit through the backplane, respectively,

wherein the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set, each of which is mounted on each of the information processing units, and accesses only one of the plurality of storage devices within each of the information processing units included in the set.

13. The computer device according to claim 12, wherein each of the storage devices contained in the same storage unit is connected to the controller mounted in the different processor units, respectively.

14. A computer device, comprising:
a plurality of processing units connected to each other;
a plurality of storage units, each of the storage units is connected to one of the processing units in a removable manner, and contains a plurality of storage devices, respectively; and
a plurality of controllers, each of the controllers is mounted on corresponding processing units respectively, and is configured to control an access to the storage devices, wherein
a storage device contained in one of the storage units forms a redundant group with a storage device contained in the other storage unit, and the storage devices forming the redundant group are connected to, and are controlled by, the single controller that is mounted on one of the processor units,
wherein the processing units are grouped into sets, and a number of processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set, each of which is mounted on each of the processing units, and accesses only one of the plurality of storage devices within each of the processing units included in the set.

15. A cluster service device, comprising:
a plurality of information processing units connected to each other, each of the information processing units is capable of functioning as a server, and contains a controller that is configured to control an access to storage devices respectively; and
a plurality of storage units, each of the storage units is connected to one of the processing units in a removable manner, and contains a plurality of storage devices respectively, wherein,
a storage device contained in one of the storage units forms a redundant group with a storage device contained in the other storage unit, and the storage devices forming the redundant group are connected to, and are controlled by the same controller that is mounted on one of the processor units
wherein the information processing units are grouped into sets, and a number of information processing units in one set is equal to a number of storage devices accessible to each of the controllers within one set, each of which is mounted on each of the information processing units, and accesses only one of the plurality of storage devices within each of the information processing units included in the set.