JP3741345B2 - Network connection disk unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk device used by being connected to a network, and more particularly to speeding up data transfer and maintaining confidentiality between disk devices connected to a network.
[0002]
[Prior art]
Several proposals have been made regarding a network-connected disk device having a network I / F.
[0003]
For example, NASD (Network-Attached ecure Disks) proposed by Garth A. Gibson et al. Of CMU (Carnegie Mellon University). Familiarity with “File Server Scaling with Network-Attached Secure Disks” at ACM International Conference on Measurement and Modeling of Computer Systems (Sigmetrics '97), Seattle, Washington, June 15-18, 1997.
[0004]
There is also Active Disks proposed by CMU's Erik Riedel, Garth Gibson and others. There has been proposed an intelligent disk device that offloads processing performed by the server to the disk device to reduce the load on the server and improve system throughput. Active Disks in The conference paper "Active Storage For Large-Scale Data Mining and Multimedia," Proc. Of the 24th International Conference on Very large Databases (VLDB '98), New York, New York, August 24-27, 1998. detailed.
[0005]
[Problems to be solved by the invention]
Since the network connection disk device is directly connected to the network, a client connected to the same network can directly access the network connection disk device. Therefore, security becomes important in the network-connected disk device. In this regard, in NASD, access rights are controlled by NASD File Manager, and security for data stored in NASD is realized.
[0006]
On the other hand, when using multiple network-attached disk devices that can offload server functions to a network where the server and clients are connected, such as Active Disk, the network-attached disk device itself is the server's Since it has a function, data can be moved between network-connected disk devices without going through a server connected to the network. Therefore, when such a network-connected disk device is used, it is possible to transfer a large amount of data without using a server, such as copying a data set or loading a database.
[0007]
However, if a large amount of data is moved between network-connected disk devices, a large amount of data flows through the network, so that the client can acquire the data by monitoring the network. In addition, when a large amount of data is transferred to the network, the load on the network increases, and the throughput of the entire information processing system including the server, client, and network connection device also decreases.
[0008]
Accordingly, an object of the present invention is to provide a disk device capable of constructing a system with high confidentiality and high throughput when an information processing system is constructed using a server, a client, and a network connection disk device. .
[0009]
[Means for Solving the Problems]
  In order to solve the above object, a network connection disk device of the present invention includes a first interface for connecting to a first network,A different kind of network than the first networkAnd a second interface for connecting to the second network. Between a client or server connected to the first network but not connected to the second network via the first networkThroughBetween the other network connection disk devices connected to the first network and the second network via the second network.Data and control informationCommunicate.
[0010]
  Another network connection device of the present invention includes a first interface for connecting to the first network and a second interface for connecting to the second network. Between clients connected to the first network but not connected to the second network via the first networkThroughDoCommunication between the server connected to the first network and the second network, and between other network connection disk devices connected to the first network and the second network Are communicated via the second network.
  Furthermore, another network connection disk device of the present invention has a first interface for connecting to the first network and a second interface for connecting to the second network. Communication is performed with a client or server that is connected to the first network but not connected to the second network via the first network, and the first network is connected to the first network via the second network. Communication between one network and another network connection disk device connected to the second network, and further receiving an access from the client via the first network; Determines whether it has obtained access rights from the server, and restricts access from the client.
  Furthermore, another network connection disk device of the present invention includes a first interface for connecting to the first network, and a second interface for connecting to a second network of a different type from the first network. Have Control information is communicated with a client or server that is connected to the first network but not connected to the second network via the first network, and is connected via the second network. Data and control information are communicated between the first network and the other network-connected disk devices connected to the second network.
  Furthermore, another network connection disk device of the present invention has a first interface for connecting to the first network and a second interface for connecting to the second network. Perform data communication and control information communication with a client connected to the first network but not connected to the second network via the first network, Communication of control information between the first network and the server connected to the second network is performed via the first or second network, and the second network is used to communicate the control information. Data communication is performed between the first network and another network-connected disk device connected to the second network.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below.
[0012]
<Example 1>
FIG. 1 shows an embodiment of an information processing system of the present invention. In this embodiment, a disk drive is assumed as the disk device 105, but it may be replaced with a RAID system composed of a plurality of disk drives.
[0013]
In this embodiment, a plurality of disk devices 105, a client 101, and a server 102 are connected to a LAN (Local Area Network) 103. A plurality of disk devices 105, clients 101, and servers 102 can communicate with each other via a LAN. Each disk device 105 includes a LAN I / F 104 for connecting to the LAN 103.
[0014]
Each disk device 105 includes a SAN I / F 106 for connection to a SAN (Storage Area Network) 107, and is also connected to the SAN. Communication between these disk devices is performed using a SAN. By using the SAN 107 for data transfer between these disk devices 105 and control information transfer, it is possible to maintain the confidentiality of the control information and suppress the influence on the LAN 103 at the time of data transfer.
[0015]
The server 102 manages data stored in a plurality of disk devices 105, and performs exclusion and directory services. That is, when the client 101 accesses the disk device 105, it always receives the directory service of the server 102.
[0016]
FIG. 2 shows an embodiment of the disk device 105 of the present invention. The MP 201 is connected to the control bus 206 via the MP I / F 202. The MP 201 gives instructions for network control, data transfer control, and drive control to the LAN I / F 104, DMAC 209, SAN I / F 106, and Drive I / F 208 connected to the control bus 206. A program running on the MP 201 is stored in the ROM 203, and the program stored in the ROM 203 is read into the RAM 204 at the time of execution, and the MP 201 reads the program from the RAM 204 and executes it. The ROM 203 and the RAM 204 are connected to the control bus 206 via the Mem I / F 205.
[0017]
  LAN I / F104 isMProtocol control for the LAN 103 is performed according to the instruction of P201.
[0018]
The DMAC 209 is connected to four data buses 207, 211, 212, and 214, the LAN I / F 104 is connected to the data bus 207, the Buffer 210 is connected to the data bus 211, the Drive I / F 208 is connected to the data bus 212, A SAN I / F 106 is connected to the data bus 214. These data buses transfer data between the LAN I / F 104 and the Buffer 210, between the Drive I / F 208 and the Buffer 210, and between the SAN I / F 106 and the Buffer 210. The DMAC 209 executes data transfer control instructed by the MP 201 using a necessary data bus.
[0019]
The SAN I / F 106 performs protocol control for the SAN 107 in accordance with an instruction from the MP 201.
[0020]
The Drive I / F 208 directly controls the drive unit 215 designated by the MP 201. The Drive I / F 208 is connected to the drive unit 215 via the bus 213, and instructs the drive unit 215 to perform positioning instructions such as seek and search and to start data transfer.
[0021]
The drive unit 215 includes an actuator 216, a head 217, and a disk 218. The actuator 216 performs positioning control, the head 217 performs data R / W, and data is recorded on the disk 218.
[0022]
Next, a read / write processing flow for the disk device 105 will be described.
[0023]
(Lead)
FIG. 3 is a diagram illustrating a processing flow in which an access request source for the disk device 105 acquires an access right. When the client 101 reads data in the disk device 105, the client 101 inquires of the server 102 about the data storage location (301).
The server 102 checks the volume in which the request data is stored, and determines whether the volume is exclusive (302). Even if the volume is not excluded, if there is an exclusion request, the volume is excluded (303, 304). Note that exclusion of a unit smaller than a volume, such as a file or database table, is managed by system software such as a higher-level file system or middleware such as a database.
[0024]
If there is no exclusion request, the client 101 is notified of the data location where the request data is stored and the access permission via the LAN 103 (305). At the same time, the server 102 notifies the disk device 105 of the access right via the LAN 103, that is, that the client 101 has acquired the volume access right (306). The contents of the notification are the disk device 105 and the accessible volume, and are encrypted and transmitted to maintain security.
[0025]
The read process flow will be described with reference to FIG. After acquiring the data storage location and access right, the client 101 next issues a read request to the disk device 105 via the LAN 103 (401). In response to the read request, the head address where the corresponding data is stored, the data size, etc. are indicated.
[0026]
The disk device 105 receives the request from the LAN 103 to the LAN I / F 104 (402). The LAN I / F 104 that has received the request notifies the MP 201 of receipt of the request via the control bus 206. After receiving the request from the LAN I / F 104, the MP 201 stores the request in the RAM 204 and analyzes the content of the request (402).
[0027]
As a result of the request analysis, first, the access right of the client 101 to the volume is checked (403).
[0028]
If there is no access right, the client 101 is notified that the access right is not available via the LAN 103, the abnormality detection is notified to the management program of the server 102, and the process is terminated (404).
[0029]
If there is an access right, the request type is checked (405).
[0030]
When the request is “read”, the MP 201 calculates the start address of the volume to be transferred based on the control table stored in the RAM 204. The MP 201 instructs the Drive I / F 208 to read the calculated start address and volume size (406). The request is indicated by the head address and the requested data size. The Drive I / F 208 issues a request to the drive unit 215 based on the request instructed by the MP 201. The drive unit 215 instructs the actuator 216 to position it at the head address of the request sent from the Drive I / F 208. The actuator 216 starts positioning to the cylinder including the indicated address (seek). Next, it waits until the corresponding address position comes to the head 217 (waiting for rotation), and when the head position of data comes, the head 217 reads the data from the disk 218 and transfers it to the Drive I / F 208.
[0031]
The MP201 instructs the drive unit 215 via the Drive I / F 208 to perform a read request, and then instructs the DMAC 209 to store the data transferred from the drive unit 215 in the Buffer 210, and the data stored in the Buffer 210. Is transferred to the LAN I / F 104. Furthermore, the MP 201 instructs the LAN I / F 104 to transfer data to the request source client 101 via the LAN 103. The DMAC 209 receives data from the Drive I / F 208 and stores it in the Buffer 210 (407).
[0032]
When more than a certain amount of data is stored in the Buffer 210, the DMAC 209 extracts the data from the Buffer 210 and transfers the data to the LAN I / F 104. The LAN I / F 104 transfers the data sent from the DMAC 209 to the request source client 101 (408).
[0033]
When all the amount indicated by the requested size has been transferred, the termination process is performed. The MP 201 notifies the client 101 of the end of the data transfer via the LAN 103, and the client 101 repeats the above processing if there is a request for the same volume thereafter, and notifies the end of the processing via the LAN 103 if there is no request. The server 102 is notified and the access right is released (409).
[0034]
(Light)
Regarding write processing, access right acquisition processing is executed prior to issuing a write request. The access right acquisition process is the same as the read process.
[0035]
The write process flow will be described with reference to FIG.
[0036]
Similar to the read process, processes 401 to 405 are performed.
[0037]
The MP 201 instructs the LAN I / F 104 to store the data transferred from the client 101 in the Buffer 210, and simultaneously instructs the DMAC 209 to store the data in the Buffer 210. When the data is transferred from the client 101, the LAN I / F 104 notifies the DMAC 209 of data reception, and the DMAC 209 receives the data and stores it in the Buffer 210 (410).
[0038]
When the buffer write is present, the end of processing is notified to the client 101 when all data is stored in the buffer. When there is no buffer write, the client 101 is notified of the end of processing after the writing to the disk 218 is completed. The MP 201 instructs the LAN I / F 104 and the DMAC 209 to store data in the Buffer 210, and then instructs the drive unit 215 to write data (411).
[0039]
Similar to the read process, the disk is positioned and the data is written to the disk 218 (412).
[0040]
Data to be written to the disk 218 is taken out from the Buffer 210 by the DMAC 209 via the data bus 211 and transferred to the Drive I / F 208 via the data bus 212. When all the amount indicated by the requested size has been transferred, the termination process is performed. The MP 201 notifies the client 101 of the end of the data transfer via the LAN 103, and the client 101 repeats the above processing if there is a request for the same volume thereafter, and notifies the end of the processing via the LAN 103 if there is no request. The server 102 is notified and the access right is released (409).
[0041]
Although the above-described access is an example of access from the client 101 to the disk device 105, access from the server 102 to the disk device 105 is performed in the same manner.
[0042]
(Data copy)
The operator can set the data access method, logical volume, access authority, volume management method, and the like of each disk device 105 with a management program on the server 102. In the present embodiment, data copy among volume management functions will be described. In the embodiment, the management program is installed on the server 102. However, the management program can be realized if it is installed on any one of the entire system of the client 101 and the disk device 105 in addition to the server 102.
[0043]
Data copy processing will be described with reference to FIG. Data copy is a process of creating a copy of a logical volume of an arbitrary disk device 105 in an arbitrary disk device 105.
[0044]
The operator selects an arbitrary volume in the management program. Next, the operator selects the disk device 105 and volume of the copy destination of the volume, and selects copy conditions (501).
[0045]
At this time, based on the configuration information of each disk device 105 stored in the server 102, the management program compares the attributes and configurations of the copy source and copy destination volumes to determine whether copying is possible (502, 503).
[0046]
If the volume attributes of the copy source and the copy destination are different, or if the copy source volume is larger than the copy destination volume, the copy is disabled, the copy is disabled and the operator is notified of the copy failure (504).
[0047]
If copying is possible, the management program instructs the copy source disk device via the LAN 103 about the volume, copy timing, and copy conditions (505).
[0048]
The timing for copying can be specified immediately, at a specified time, or at regular time intervals. Access and priority can be specified as copy conditions. In specifying access, it is possible to select whether or not only reading of the copy source disk device 105 is possible. When the highest priority is specified in the copy processing priority, the disk device 105 executes the copy process with priority over other data read / write processes. On the other hand, when the priority is the lowest, since requests other than the copy process are given priority, the copy process is executed only when the disk device 105 is in an idle state (a state that does not hold a request to be processed). .
[0049]
Upon receiving the instruction, the copy source disk device restricts access to the volume for which read permission or inaccessibility is designated (506). Thereafter, the access restriction on the volume is continued until copying is completed.
[0050]
The copy destination disk device 105 also restricts volume access in the same manner as the copy source disk device 105 (507).
[0051]
After the copy preparation is completed, the MP 201 of the copy destination disk device 105 notifies the copy source disk device 105 that copying is possible via the SAN 107.
[0052]
After receiving the notification, the copy source disk device 105 starts the copy process (509).
[0053]
If the data transfer is not executed for a certain period of time, the copy destination disk device 105 notifies the management program of the abnormality detection, and the management program that has received the abnormality detection interrupts the copy process. In addition, when the preparation completion notification is not notified from the copy destination disk device 105 even after a certain period of time, the copy source disk device 105 notifies the management program of the abnormality detection, and the management program that has received the abnormality detection copies Stop processing.
[0054]
When a large amount of data is transmitted via the LAN 103 as in the copy process, a load is applied to the LAN 103 and the throughput of the entire system is reduced. When a large amount of data is transferred via the LAN 103, the client 101 and the server 102 can steal the data, and it is difficult to maintain confidentiality. Therefore, by transferring these data via the SAN 107, it is possible to reduce the load on the LAN 103 and maintain confidentiality.
[0055]
An embodiment of copy processing with a high priority will be described with reference to FIG. The MP 201 of the copy source disk device 105 calculates the start address of the volume to be transferred based on the control table stored in the RAM 204 (601).
[0056]
The MP 201 of the copy source disk drive instructs the drive unit 215 to read the calculated start address and volume size (602).
[0057]
The drive unit 215 instructs the actuator 216 to position it at the head address. The actuator 216 starts positioning to the cylinder including the indicated address (seek). Next, it waits until the corresponding address position reaches the head 217 position (waiting for rotation), and when it reaches the head position of the data, the head 217 reads the data from the disk 218 and transfers it to the Drive I / F 208 (603).
[0058]
After the positioning is completed, the data transferred from the drive unit 215 is stored in the Buffer 210, and the data stored in the Buffer 210 is transferred to the copy destination disk device 105 via the SAN 107 (604). The copy destination disk device stores the received data in Buffer 210 (605).
[0059]
In the copy destination disk device 105, when the MP 201 receives the data reception, the MP 201 stores the data in the Buffer 210 (605).
[0060]
Next, the position for storing the transferred data is calculated based on the copy request issued from the management program and the management table stored in the RAM 204, and the actuator 216 starts positioning to the head position (606).
[0061]
After positioning, the drive unit 215 writes the data stored in the Buffer 210 to the disk 218 (607).
[0062]
The above processing is executed until the volume copy is completed. However, if the MP201 of the copy source / destination disk device 105 detects an error such as a transfer error in the middle of processing, the copy source is to the copy destination, and the copy destination is to the copy source disk device 105 MP201. The abnormality is notified via the SAN 107, and the abnormality is notified to the management program installed in the server 102 via the LAN 103, and the processing is interrupted. When the process is completed without an error, the MP 201 of the copy source disk device 105 first notifies the copy destination disk device 105 via the SAN 107 that the copy has been completed using the SAN I / F 106. . When receiving the copy completion, the MP 201 of the copy destination disk device 105 ends the copy process. Next, the management program on the server 102 is notified of the end of copying via the LAN 103. When the management program on the server 102 receives the end of copying, the management program notifies the operator that the copying has ended and ends the copying process.
[0063]
When the copy source disk device 105 finishes the copy process, it notifies the copy destination disk device 105 and the management program on the server 102 of the end of the copy (608). Thereafter, the access right control of the volume used for the copy is canceled and the copy process is terminated.
[0064]
By performing the copy process preferentially in this way, data can be copied in a short time.
[0065]
(When copy processing priority is low)
Next, a copy process when the priority is the lowest will be described. When the priority of the copy process is low, the copy process is executed only when no other request to be executed by the copy source disk device 105 is held. Specifically, copy processing is executed when the drive unit 215 is not executing processing.
[0066]
The low-priority data copy process will be described with reference to the flowchart of FIG. When the priority of the data copy process is low, access to all the copy source volumes is permitted. The MP 201 of the copy source disk device 105 first determines the size of data to be transferred in a single process. In this embodiment, 1 MB is used, but the transfer size is arbitrary. Next, it is checked whether there is a request to be executed to the drive unit 215 (701). If there is a request to be executed, the copy process is temporarily stopped and the request is executed (702). Next, processing similar to the processing 601 to 608 described in FIG. 6 is performed (703 to 709).
[0067]
The above processing is executed until 1 MB of data is transferred. After the transfer of 1 MB of data, it is checked whether there is a request to be executed again in the copy source disk device 105. If there is a request to be executed, the request is executed, and after executing the request, the presence of the request is checked again. If there is no request to be executed, the copy process is continued. When the data copies of all the volumes have been transferred, the following termination process is executed (710).
[0068]
However, if the MP201 of the copy source / destination disk device 105 detects an error such as a transfer error in the middle of processing, the copy source is to the copy destination, and the copy destination is to the copy source disk device 105 MP201. The abnormality is notified via the SAN 107, and the abnormality is notified to the management program installed in the server 102 via the LAN 103, and the processing is interrupted. When the process is completed without an error, the MP 201 of the copy source disk device 105 first notifies the copy destination disk device 105 via the SAN 107 that the copy has been completed using the SAN I / F 106. . When receiving the copy completion, the MP 201 of the copy destination disk device 105 ends the copy process. Next, the management program on the server 102 is notified of the end of copying via the LAN 103. When the management program on the server 102 receives the end of copying, the management program notifies the operator that the copying has ended and ends the copying process. The MP 201 of the copy source disk device 105 notifies the copy destination disk device 105 and the management program on the server 102 of the end of copy (710), and then ends the copy process.
[0069]
By performing copying between read / write requests in this way, backup can be performed without affecting normal processing.
[0070]
<Example 2>
FIG. 8 shows another embodiment of the information processing system of the present invention. In this embodiment, a disk drive is shown as the disk device 805. However, the disk device 805 can also be configured by a device such as a RAID system including a plurality of disk drives.
[0071]
This embodiment is different from the first embodiment in that not only the disk device 805 but also the server 803 is connected to the SAN 807. The SAN 807 is used when the server 802 notifies the disk device 805 of access rights. As a result, data transmitted between the server 803 and the disk device 806 can be isolated from the client, and confidentiality can be maintained. Different protocols may be used for the LAN 803 and the SAN 807. For example, the SAN 807 supports a lower latency and higher throughput protocol than the LAN 803, and can realize a communication environment depending on data characteristics.
[0072]
Hereinafter, processing for issuing a read / write request from the server 802 to the disk device 805 will be described.
[0073]
(Lead)
Also for the read process of this embodiment, an access right acquisition process is executed prior to issuing a read request. The access right acquisition process performs the process shown in the flowchart of FIG.
[0074]
The process after acquiring the access right will be described with reference to FIG. After acquiring the access right, the server 802 determines whether to access the data to be accessed through the SAN 807 with high confidentiality or low latency and high throughput. The condition of the management information such as the directory of the data type and the important volume is obtained by determining the volume information from the management program. As for the network to be used, the user designates the management program with high and low confidentiality, high and low throughput, and high and low latency. In addition to the management program information, the determination is made in consideration of the access characteristics of the application on the server 802.
[0075]
Next, if access via the SAN 807 is designated, the processing shown in FIG. 10 is executed, and if not via the SAN 807, access via the LAN 803 shown in FIG. 4 is executed. Access via the LAN 803 is the same as in the first embodiment.
[0076]
FIG. 10 shows read processing and write processing via the SAN 807. The read processing and write processing via the SAN 807 are the same as the processing described with reference to FIG.
[0077]
【The invention's effect】
As described above, according to the present invention, it is possible to perform highly confidential data copying and data transfer by connecting a plurality of network-connected disk devices with a SAN, and simultaneously reduce network traffic (load). It becomes possible to reduce.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration example of an information processing system according to the present invention.
FIG. 2 is a diagram showing a configuration example of a disk device according to the present invention.
FIG. 3 is a diagram showing a flow of access right acquisition processing for a disk device in the information processing system of FIG. 1;
4 is a diagram showing a flow when a read / write process is performed on a disk device via a LAN in the information processing system of FIG. 1;
FIG. 5 is a diagram showing a flow of data copy processing of the disk device of the present invention.
FIG. 6 is a diagram showing a flow of copy processing of the disk device of the present invention.
FIG. 7 is a diagram showing a flow of copy processing of the disk device of the present invention.
FIG. 8 is a diagram showing a configuration example of an information processing system according to the present invention.
9 is a diagram showing a flow when a read / write process is performed on a disk device in the information processing system of FIG. 8;
10 is a diagram showing a flow when a read / write process is performed on a disk device via a SAN in the information processing system of FIG. 8;
[Explanation of symbols]
101 ... Client, 102 ... Server, 103 ... LAN, 104 ... LAN I / F, 105 ... Disk device, 106 ... SAN I / F, 107 ... SAN, 801 ... -Client, 802 ... LAN, 803 ... Server, 804 ... LAN I / F, 805 ... SAN I / F, 806 ... Disk device, 807 ... SAN.

Claims (10)

A network-connected disk device having a first interface for connecting to a first network and a second interface for connecting to a second network of a different type from the first network ,
Communicating with a client or server connected to the first network but not connected to the second network via the first network;
A network connection characterized in that data and control information are communicated between the first network and another network-connected disk device connected to the second network via the second network. Disk unit.   2. The network-connected disk device according to claim 1, wherein the control information encrypted is received from the server. A network-connected disk device having a first interface for connecting to a first network and a second interface for connecting to a second network,
Via the first network, the connected to the first network is performed communication between a client that is not connected to the second network, and said first network and said second network The communication between the server connected to the server and the communication between the first network and the other network connection disk device connected to the second network are performed via the second network. network connections disk apparatus according to claim.   4. The network-connected disk device according to claim 1, wherein access from the client is restricted according to control information from the server.   5. The data to be copied is transmitted to the other network-connected disk device via the second network when receiving a data copy instruction from the server. The network connection disk device as described in 1. A first interface for connecting to a first network;
A network connection disk device having a second interface for connecting to a second network,
Communicating with a client or server connected to the first network but not connected to the second network via the first network;
Communication is performed between the first network and another network connection disk device connected to the second network via the second network, and further via the first network, Receive access from the above client,
Determine whether the client has access rights from the server,
A network-connected disk device, wherein access from the client is restricted. A first interface for connecting to a first network;
A network-attached disk device having a second interface for connecting to the second network of a different type from the first network ,
The control information is communicated with the client or the server connected to the first network but not connected to the second network via the first network.
A network connection characterized in that data and control information are communicated between the first network and another network-connected disk device connected to the second network via the second network. Disk unit. A first interface for connecting to a first network;
A network connection disk device having a second interface for connecting to a second network,
Data communication and communication of control information with a client connected to the first network but not connected to the second network via the first network, and the first or second Communication of control information between the server connected to the first network and the second network via the network,
A network-connected disk device that performs data communication between the first network and another network-connected disk device connected to the second network via the second network. Via the first network, communicate with the client or the server the data to be read or written or the control information regarding the read or write processing of the data,
The data is communicated with the other network-connected disk device via the second network with the copy processing priority set for the data to be copied.
The network-connected disk device according to claim 1, wherein: Via the first network, communicate the data to be read or written or the control information regarding the read or write processing of the data with the client or the server,
The data is communicated with the other network-connected disk device via the second network with the copy processing priority set for the data to be copied.
The network-connected disk device according to claim 7, wherein:

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