JP2008003815A - Computer system, network boot system, method of switching os image, and program for switching os image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of switching OS images or the like for ensuring both the image retaining function and volume efficiency of a plurality of OSs, reducing the time required to update the OSs, and maintaining conventional OS images that are reliable. <P>SOLUTION: A computer system 10 includes: an OS image update means 1 for creating the latest OS image 3 and writing it in an external storage device; a snapshot creating means 5 for creating a snapshot OS image 4 prior to the start of the OS image update means and writing it in the external storage device; a boot image selecting means 5 for selecting either the latest OS image or the snapshot OS image as a boot OS image; and a boot means 6 for reading the boot OS image from the external storage device and writing it in a main storage device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for starting a computer using a plurality of versions of an operating system (hereinafter referred to as “OS”) and selecting one of the operating systems, and in particular, achieves both a function of retaining a plurality of OS images and capacity efficiency. The present invention relates to OS switching technology.

Conventionally, there are roughly the following two methods for providing a plurality of versions of a file group constituting an OS image required for starting up a computer system.
One is a method of holding a set of multiple file groups. In this method, file groups that maintain consistency with each other are collected under a specific directory or naming rule. The OS image to be started can be changed by switching the.

The other method is a method in which an OS image that is normally activated is held as a normal file image, and other versions of the OS image are archived as files having a difference from the current version. It is mainly used for the purpose of making it possible to return to the previous version of the OS image when there is a problem when the OS is updated.
Under this method, restoration from the differential file archive is required to activate an OS image other than the OS version that is normally activated.

An example of such a method is described in Patent Document 1.
In the software installation method described in this document, the second software upgraded from the first software is installed in the computer while the first software stored in the computer is executable in the following procedure.
First, it is determined whether each file constituting the second software is the same as or different from each file of the first software. If they are the same, the first software file determined to be the same is linked so that it can be used as the second software file. On the other hand, if they are different, the second software file determined to be different is installed.

JP 2004-206353 A

Although the former method having a plurality of file groups is easy to switch, it is very bad in terms of capacity efficiency. In particular, in the case of the OS, it is wasteful to have a plurality of copies for most other unmodified parts even if partial correction / update is performed.
Although the latter method improves the capacity efficiency, switching from the boot OS image requires recovery from the archive, and maintaining multiple versions of the OS makes it extremely difficult to maintain the consistency of the archive contents. There is also a drawback.

  In the above situation, the present invention achieves both a function of retaining a plurality of OS images and capacity efficiency, shortening the time required for upgrading the OS, and maintaining a reliable conventional OS image. An object of the present invention is to provide an OS image switching method that can be used.

  The computer system of the present invention includes an OS image update unit that updates an OS image that is an image of an operating system, generates a latest OS image, and writes the OS image to an external storage device, and an OS before update prior to the operation of the OS image update unit. A snapshot generation unit that generates a snapshot OS image that is a snapshot of an image and writes the snapshot OS image to an external storage device; a boot image selection unit that selects one of the latest OS image and the snapshot OS image as a boot OS image; Boot means for reading the boot OS image from the external storage device and writing it to the main storage device (claims 1 to 3).

According to the computer system, prior to the update of the latest OS image, a snapshot OS that is a snapshot of the latest OS image at that time is generated and stored in the external storage device. When starting up the computer system, the boot OS image is selected to start up the OS.
Therefore, it is possible to achieve both the function of retaining the images of a plurality of OSs and the capacity efficiency, reduce the time required for upgrading the OS, and reliably retain the OS image before the update.

  In the computer system, the snapshot generation unit may generate a snapshot OS image for each file, and the boot image selection unit may notify the boot unit of the reference start position of the boot OS image in the external storage device. (Claim 2).

  In the computer system, the snapshot generation unit generates a snapshot OS image for each device, and the boot image selection unit notifies the boot unit of information specifying a device in which the boot OS image is written. (Claim 3).

The network boot system of the present invention includes a boot server and a client.
The boot server updates the OS image to generate the latest OS image and writes it to the external storage device, and the snapshot OS image that is a snapshot of the OS image before the update prior to the operation of the OS image update unit. And a boot OS image transmission unit that transmits a boot OS image that is a latest OS image or a snapshot OS image designated by the client to the client.
The client selects one of the latest OS image and the snapshot OS image as a boot OS image, and transmits a OS image transmission request including information for specifying the boot OS image to the boot server; Boot means for receiving the boot OS image transmitted from the boot server in response to the image transmission request and writing the boot OS image in the main storage device.

According to the network boot system, the boot image selection unit operates on the client, and the boot boot server holding the OS image can provide a plurality of versions of OS images to the client boot image selection unit. .
Therefore, it is possible to greatly reduce the trouble of generating an OS image including different setting information for each client and the storage cost thereof.

  In the OS image switching method according to the present invention, a snapshot generation process that generates a snapshot OS image that is a snapshot of an OS image that is an image of an operating system and writes the snapshot OS image to an external storage device, and the latest OS image by updating the OS image. OS image update process for generating and writing to the external storage device, a boot image selection step for selecting one of the latest OS image and the snapshot OS image as a boot OS image, and reading the boot OS image from the external storage device The OS image used for starting up the computer is switched by the boot process written in the main storage device (claims 5 to 7).

According to the OS image switching method, a snapshot OS that is a snapshot of the latest OS image at that time is generated and stored in the external storage device prior to the update of the latest OS image. When starting up the computer system, the boot OS image is selected to start up the OS.
Therefore, it is possible to achieve both the function of retaining the images of a plurality of OSs and the capacity efficiency, reduce the time required for upgrading the OS, and reliably retain the OS image before the update.

  In the OS image switching method, a snapshot OS image is generated in file units in the snapshot generation step, a reference start position in the external storage device of the boot OS image is acquired in the boot image selection step, and reference start is started in the boot step. The boot OS image may be read according to the position (claim 6).

  In the OS image switching method, a snapshot OS image is generated for each device in the snapshot generation step, and boot device selection information for specifying a device in which the boot OS image is written is acquired in the boot image selection step. In the boot process, the boot OS image may be read from the device indicated in the boot device identification information.

  The network boot method of the present invention includes a snapshot generation step in which a boot server generates a snapshot OS image that is a snapshot of an OS image that is an image of an operating system, and writes the snapshot OS image to an external storage device. An OS image update step of updating the OS to generate the latest OS image and writing it to the external storage device; a boot image selection step in which the client selects one of the latest OS image and the snapshot OS image as a boot OS image; A transmission request step in which the client transmits an OS image transmission request including information identifying the boot OS image to the boot server, and a boot OS in which the boot server transmits the boot OS image to the client in response to the OS image transmission request. And image transmission process, the client performs the startup of the client by the boot process of writing receives the transmitted boot OS image from the boot server to the main memory (claim 8).

According to the network boot method, the boot image is selected by the client, and the boot boot server that holds the OS image can provide the client with a plurality of versions of the OS image.
Therefore, it is possible to greatly reduce the trouble of generating an OS image including different setting information for each client and the storage cost thereof.

  The OS image switching program of the present invention generates a snapshot OS image, which is a snapshot of an OS image, which is an image of an operating system, and updates the OS image and updates the OS image. OS image update processing for generating an OS image and writing it to an external storage device, boot image selection processing for selecting one of the latest OS image and snapshot OS image as a boot OS image, and a boot OS image from the external storage device A boot process for reading and writing to the main memory is executed (claims 9 to 11).

According to the OS image switching program, prior to updating the latest OS image, a snapshot OS that is a snapshot of the latest OS image at that time is generated and stored in the external storage device. When starting up the computer, the boot OS image is selected to start up the OS.
Therefore, it is possible to achieve both the function of retaining the images of a plurality of OSs and the capacity efficiency, reduce the time required for upgrading the OS, and reliably retain the OS image before the update.

  In the OS image switching program, the snapshot generation process generates a snapshot OS image in file units, the boot image selection process acquires the reference start position of the boot OS image in the external storage device, and the boot process starts reference. The boot OS image may be read according to the position (claim 10).

  In the OS image switching program, in the snapshot generation process, a snapshot OS image is generated for each device, and in the boot image selection process, boot device identification information for identifying a device in which the boot OS image is written is acquired. In the boot process, the boot OS image may be read from the device indicated by the start device specifying information.

  The network boot program of the present invention generates a snapshot OS image that is a snapshot of an OS image on a boot server and writes it to an external storage device, and updates the OS image to generate the latest OS image and externally. An OS image update process to be written to the storage device and a boot OS image transmission process for transmitting a boot OS image, which is a latest OS image or a snapshot OS image designated by the client, to the client are executed. A boot image selection process for selecting one of the snapshot OS images as a boot OS image and an OS image transmission request including information for specifying the boot OS image are transmitted to the boot server. Executing the boot process of writing to the main memory receives the boot OS image sent from the boot server in response to the transmission request (claim 12).

According to the network boot program, the boot image is selected by the client, and the boot boot server holding the OS image can provide a plurality of versions of the OS image to the client.
Therefore, it is possible to greatly reduce the trouble of generating an OS image including different setting information for each client and the storage cost thereof.

According to the present invention, prior to the update of the latest OS image, a snapshot OS that is a snapshot of the latest OS image at that time is generated and stored in the external storage device. When starting up the computer, the boot OS image is selected to start up the OS.
Therefore, it is possible to achieve both the function of retaining the images of a plurality of OSs and the capacity efficiency, reduce the time required for upgrading the OS, and reliably retain the OS image before the update.

The configuration and operation of the computer system 10 according to the first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a functional block diagram of the computer system 10.
The computer 10 includes an OS image update unit 1, a file system 2, a boot unit 6, and a boot image selection unit 7 as functional blocks. The file system 2 includes a snapshot generation unit 5, a latest OS image 3, and a snapshot OS image 4.
The computer system 10 includes a CPU (Central Processing Unit), an external storage device, a main storage device, and an input / output device as hardware.

  The OS image update unit 1 updates an OS image stored in an external storage device such as a hard disk device to generate a latest OS image 3 and writes the latest OS image 3 in the external storage device. The OS image update unit 1 is activated by an instruction from the user of the computer system 10 or an automatic update program of the OS when there is a need to update the OS image for reasons such as defect correction or functional enhancement. Performs replacement of files constituting the OS image.

  The file system 2 holds a plurality of OS images composed of files necessary for starting up the computer system 10. Specifically, the latest OS image 3 generated by the OS image update unit and one or more snapshot OS images 4 generated by the snapshot generation unit 5 are held.

Prior to the operation of the OS image update unit 1, the snapshot generation unit 5 generates a snapshot OS image 4 that is a snapshot of the latest OS image 3 at that time, and writes the snapshot OS image 4 to an external storage device such as a hard disk device. A snapshot is created each time the OS image update unit 1 is operated, and a plurality of versions of the snapshot OS image 4 are held.
When the snapshot function provided by the file system 2 is used, even if the latest OS image 3 is updated after the snapshot is taken, the software operating on the computer system 10 refers to the latest OS image at the time of taking the snapshot. can do.
In the computer system 10, even when a problem occurs in the system due to the replacement of the files constituting the OS image, the boot OS selection unit 7 described later can select and start the snapshot OS image 4 before replacement. it can.

The specific implementation method and reference method of the snapshot function are not essential in the present invention.
However, in order to simplify the following description, snapshots are taken in file system units, and only the parts that differ between the latest part (latest OS image 3) and the snapshot part (snapshot OS image 4). The copy-on-write method is used to share the same storage part for the part that is held separately and is the same for the latest part and the snapshot. For reference, the snapshot is specified in the hierarchical directory system. Suppose that the file system image at the time of taking a snapshot is visible under the directory with the name to be created.

  The boot means 6 operates when the computer system 10 is powered on or receives a reset signal, reads the OS image from the external storage device, and writes (loads) it to the main storage device such as RAM. . The OS image to be written to the main storage device is notified from the boot image selection means 7.

The boot image selection unit 7 operates when called by the boot unit 6 and is used for booting from the latest OS image 3 and snapshot OS image 4 stored in the external storage device (boot OS image). Select.
In this selection, for example, a list of selectable OS images and an interface for selection are displayed on the display device, and the selection is performed according to the input of the user of the computer system 10. Further, usually, the latest OS image 3 is selected. For example, when the user performs a predetermined special activation operation such as turning on the power while pressing a specific key on the keyboard, a screen for prompting selection May be output.
When the snapshot reference method exemplified above is adopted, the snapshot OS image 4 and the latest OS image 3 have the same logical structure except only the reference start directory position in the file system 2. ing.
Therefore, in this case, the boot image selection unit 7 notifies the boot unit 6 of the reference start position of the boot OS image, and the boot unit 6 starts the startup process according to this notification.

Next, the operation of the computer system 10 will be described.
FIG. 2A is a flowchart for explaining the update operation of the latest OS image 3 of the computer system 10.
First, the snapshot generation means 5 creates a snapshot of the latest OS image 3 at that time, and writes it in the external storage device as the snapshot OS image 4 (S101).
Next, the OS image update unit 1 updates the latest OS image 3 by replacing a file constituting the latest OS image 3 or the like.

FIG. 2B is a flowchart for explaining the operation when the computer system 10 is started.
When the computer system 10 is turned on (S111), the boot unit 6 calls the boot image selection unit 7, and the boot image selection unit 7 selects the boot OS image from the latest OS image 3 and the snapshot OS image 4. Select (S112).
The boot image selection unit 7 notifies the boot unit 6 of the reference start position of the selected boot OS image (S113).
The boot unit 6 reads the boot OS image from the external storage device and writes it to the main storage device based on the reference start position notified in S113. The CPU of the computer system 10 starts the OS by executing a program included in the OS image written in the main storage device (S114).

In the description so far, the snapshot creation method is premised on a file system unit basis. However, if a snapshot can be referred to, the snapshot implementation method is not essential in the present invention. In a storage apparatus having a snapshot, the present invention can be similarly applied to a form in which the latest OS image 3 and the snapshot OS image 4 are viewed as separate devices. In this case, the boot image selection means 7 selects a startup device.
That is, the present invention can be similarly applied to an environment having a file system level snapshot and an environment having a block device level snapshot.

Next, the effect of the computer system 10 will be described.
The first effect is to increase the efficiency of the actual capacity necessary for holding a plurality of versions of OS images and the like.
The reason is that the efficiency function related to holding a plurality of snapshots of the snapshot function provided in the file system 2 can be used as it is.
The second effect is that a plurality of versions of OS images can be maintained while maintaining the integrity almost completely, and high-speed image updating is possible.
The reason is that the snapshot generation means 5 quickly generates the snapshot OS image 4 by the nap shot function, and the file system 2 maintains a plurality of versions of the snapshot OS image while maintaining consistency. Because it can.
As described above, according to the computer system 10, while using the existing technology such as the boot image selection means, the drawbacks of the multiple versions of the OS image holding means so far are compensated, and both capacity efficiency and operability are achieved. Can be improved.

Further, the present invention is not limited to a single computer boot image holding method, and is also applied to a method of holding a plurality of versions of OS images on a boot server and providing an image for booting a plurality of computers via a network. it can.
FIG. 3 shows a functional block diagram of the network boot system 20 which is an example of such an embodiment.
The network boot system 20 includes a boot server 21 that holds an OS image and a plurality of clients 22 connected to the boot server 21 via a network such as a LAN (Local Area Network).
The client 22 requests the boot server 21 to transmit an OS image at the time of activation, and activates the OS using the OS image transmitted in response to this request.

The boot server 21 is a server computer having a CPU, a main storage device, an external storage device, and a communication device. The boot server 21 has an OS image update unit 1, a file system 2 and a snap having functions similar to those described in the first embodiment. The file system 2 includes the latest OS image 3 and the snapshot OS image 4. A plurality of latest OS images 3 and snapshot OS images 4 are stored for each client or each group of clients. The boot server 21 includes boot OS image transmission means 23 in addition to these components.
The boot OS image transmission unit 23 transmits the latest OS image or snapshot OS image (boot OS image) designated by the client 22 to the client 22.

  The client 22 is a personal computer including a CPU, a main storage device, an external storage device, and a communication device, and includes a boot unit 6 and a boot image selection unit 7 having functions similar to those described in the first embodiment. Yes. However, instead of notifying the boot unit 6 of the selected boot OS image, the boot image selection unit 7 boots a boot OS image transmission request including information specifying the boot OS image, such as a version number and a snapshot creation date. Send to server 21. Further, the boot unit 6 writes the boot OS image received from the boot server 21 in the main storage device.

FIG. 4 is a flowchart for explaining the operation at the time of starting the network boot system 20. The operation of updating the latest OS image of the boot server 21 is the same as that shown in FIG.
When the power of the client 22 is turned on (S201), the boot unit 6 calls the boot image selection unit 7, and the boot image selection unit 7 updates the latest OS image 3 and the snapshot OS image 4 held by the boot server 21. A boot OS image is selected from (S202).
The boot image selection unit 7 transmits a boot OS image transmission request including information for specifying the selected boot OS image to the boot server 21 (S203).
Upon receiving this request, the boot OS image transmission means 23 of the boot server 21 reads the boot OS image from the external storage device and transmits it to the client 21 (S204).
The boot unit 6 of the client 22 writes the received boot OS image in the main storage device. The CPU of the client 22 starts the OS by executing a program included in the OS image written in the main storage device (S205).

Thus, according to the network boot system 20, the boot image selection means 7 operates on the client 22, and the boot server 21 holding the file system 2 uses the method based on the present invention to select the boot image of the client 22. A plurality of versions of OS images can be provided to the means 7.
In this case, it is possible to greatly reduce the trouble of generating an OS image including different setting information for each client and the storage cost thereof.

It is a functional block diagram of the computer system which is the 1st Embodiment of this invention. FIG. 2A is a flowchart for explaining the update operation of the latest OS image of the computer system. FIG. 2B is a flowchart for explaining the operation at the time of starting the computer system. It is a functional block diagram of the network boot system which is the 2nd Embodiment of this invention. It is a flowchart explaining the operation | movement at the time of starting of the network boot system of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 OS image update means 2 File system 3 Latest OS image 4 Snapshot OS image 5 Snapshot generation means 6 Boot means 7 Boot image selection means 10 Computer system 20 Network boot system 21 Boot server 22 Client 23 Boot OS image transmission means

Claims (12)

An OS image update means for updating an OS image, which is an image of an operating system, to generate a newest OS image and write it to an external storage device;
Snapshot generating means for generating a snapshot OS image, which is a snapshot of the OS image before update, prior to the operation of the OS image updating means, and writing the snapshot OS image to the external storage device;
Boot image selection means for selecting one of the latest OS image and the snapshot OS image as a boot OS image;
Booting means for reading the boot OS image from the external storage device and writing it into a main storage device.   The snapshot generation unit generates the snapshot OS image in file units, and the boot image selection unit notifies the boot unit of a reference start position of the boot OS image in the external storage device. The computer system according to claim 1.   The snapshot generation unit generates the snapshot OS image on a device basis, and the boot image selection unit notifies the boot unit of information specifying the device in which the boot OS image is written. The computer system according to claim 1, wherein the computer system is characterized. In a network boot system for starting a client connected to the boot server by using an OS image which is an image of an operating system stored in the boot server,
The boot server is
OS image update means for updating the OS image to generate the latest OS image and writing it in the external storage device;
Snapshot generating means for generating a snapshot OS image, which is a snapshot of the OS image before update, prior to the operation of the OS image updating means, and writing the snapshot OS image to the external storage device;
Boot OS image transmission means for transmitting to the client a boot OS image that is the latest OS image or the snapshot OS image designated by the client;
The client
Boot image selection means for selecting one of the latest OS image and the snapshot OS image as the boot OS image and transmitting an OS image transmission request including information for specifying the boot OS image to the boot server; ,
A network boot system comprising boot means for receiving the boot OS image transmitted from the boot server in response to the OS image transmission request and writing the boot OS image in a main storage device. In a method of switching an OS image used for starting a computer,
A snapshot generation step of generating a snapshot OS image that is a snapshot of an OS image that is an image of an operating system and writing the snapshot OS image to an external storage device;
An OS image update step of updating the OS image to generate a latest OS image and writing it to the external storage device;
A boot image selection step of selecting one of the latest OS image and the snapshot OS image as a boot OS image;
A boot step of reading the boot OS image from the external storage device and writing it to a main storage device.   In the snapshot generation step, the snapshot OS image is generated in units of files, in the boot image selection step, a reference start position in the external storage device of the boot OS image is acquired, and in the boot step, the reference start 6. The OS image switching method according to claim 5, wherein the boot OS image is read according to a position.   In the snapshot generation step, the snapshot OS image is generated in units of devices, and in the boot image selection step, boot device identification information for identifying the device in which the boot OS image is written is acquired, and the boot 6. The OS image switching method according to claim 5, wherein in the step, the boot OS image is read from a device indicated by the boot device specifying information. In a network boot method for starting a client network-connected to the boot server using an OS image that is an image of an operating system stored in a boot server,
A snapshot generation step in which the boot server generates a snapshot OS image that is a snapshot of an OS image that is an image of an operating system and writes the snapshot OS image to an external storage device;
An OS image update step in which the boot server updates the OS image to generate a latest OS image and writes the latest OS image in the external storage device;
A boot image selection step in which the client selects one of the latest OS image and the snapshot OS image as the boot OS image;
A transmission request step in which the client transmits an OS image transmission request including information specifying the boot OS image to the boot server;
A boot OS image transmission step in which the boot server transmits the boot OS image to the client in response to the OS image transmission request;
A network boot method, comprising: a boot process in which the client receives the boot OS image transmitted from the boot server and writes the boot OS image to a main storage device. On the computer,
A snapshot generation process that generates a snapshot OS image that is a snapshot of an OS image that is an image of an operating system and writes the snapshot OS image to an external storage device;
An OS image update process for updating the OS image to generate the latest OS image and writing it in the storage device;
A boot image selection process for selecting one of the latest OS image and the snapshot OS image as a boot OS image;
An OS image switching program for executing a boot process of reading the boot OS image from the external storage device and writing it to a main storage device.   In the snapshot generation process, the snapshot OS image is generated in file units. In the boot image selection process, a reference start position of the boot OS image in the external storage device is acquired. In the boot process, the reference start is started. The OS image switching program according to claim 9, wherein the boot OS image is read according to a position.   In the snapshot generation process, the snapshot OS image is generated in units of devices, and in the boot image selection process, boot device identification information for identifying the device in which the boot OS image is written is acquired, and the boot 10. The OS image switching program according to claim 9, wherein in the processing, the boot OS image is read from a device indicated by the boot device specifying information. In a network boot program for starting a client network-connected to the boot server using an OS image which is an image of an operating system stored in the boot server,
In the boot server,
A snapshot generation process that generates a snapshot OS image that is a snapshot of the OS image and writes the snapshot OS image to an external storage device;
An OS image update process for updating the OS image to generate the latest OS image and writing it to the external storage device;
A boot OS image transmission process for transmitting a boot OS image that is the latest OS image or the snapshot OS image designated by the client to the client;
To the client,
A boot image selection process for selecting one of the latest OS image and the snapshot OS image as the boot OS image;
An OS image transmission request including information specifying the boot OS image is transmitted to the boot server, and the boot OS image transmitted from the boot server is received in response to the OS image transmission request and written to the main storage device. A network boot program characterized by executing a boot process.

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