JP2006215615A - Information recording and reproducing apparatus and method for controlling it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To implement priority processing on requests to read or write a medium volume of higher priority depending on the condition of the load on a host interface, thereby preventing delay in processing any important volume even if the load on the host interface is high. <P>SOLUTION: In an information recording and reproducing apparatus, a medium library device 2 is provided with an instruction queue management part for managing process requests coming from a higher-level device; a reference table for registering the priority of each medium; and a drive control part that executes the process requests sent from the instruction queue management part. When the load on the host interface gets higher, the instruction queue management part causes the process requests to be fetched and executed preferentially depending on the priority of each medium registered in the reference table. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information recording / reproducing apparatus, and more particularly to an apparatus for determining the order of read / write processing based on the priority of a tape volume in a magnetic tape library control apparatus and a control method therefor.

  Conventionally, in a magnetic tape library apparatus having a magnetic tape transport means and a plurality of magnetic tape drives, when read / write processing for a plurality of tape volumes is executed simultaneously, the I / O processing capacity of the host interface is set as an upper limit. By controlling the distribution to be equal to the magnetic tape drive currently processing, the processing capacity of the entire magnetic tape library apparatus is improved. However, in the simultaneous read / write processing of a plurality of tape volumes in the conventional apparatus, since the input / output processing capability of the host interface is distributed to the tape volumes being simultaneously executed, the data transfer processing capability in units of tape volumes is reduced. There was a problem.

  On the other hand, in a data storage system that records data on a plurality of magnetic disk devices in a duplicated manner, when a write request is received, the magnetic disk device with the smallest load is selected and a write request command is input, and another magnetic disk in the background It has been proposed to dynamically adjust the throughput performance of a virtual disk device by executing a copy to the device, and when a read request is received, a read request command is put into the queue of the magnetic disk device with the smallest load. (For example, Patent Document 1).

  Also, in a system that mirrors the primary and secondary disk subsystems, the copy priority is given to the copy source logical volume group, and the priority is given to the copy of the logical volume group with the higher priority. It has been proposed to improve the safety of data by always pre-copying important data with high priority (for example, Patent Document 2).

  In addition, host I / O requests and internal I / O requests are handled separately, and the number of processing requests issued to virtual disks can be individually limited, giving priority to host I / O and balancing the load on the device. A storage system that is controlled has been proposed (for example, Patent Document 3). Thereby, it is possible to manage the load of internal I / O, that is, rebuild or copyback, while maintaining a certain level of host I / O response.

JP 2001-125750 A JP 2003-6016 A JP 2004-295860 A

  However, the system described in Patent Document 1 is to queue a disk device having the smallest load among a plurality of disk devices, and sets the processing order according to the priority of the medium itself. It is not a thing. The system described in Patent Document 2 determines the order of mirroring processing based on the importance level of the copy source logical disk, but does not process read / write requests from the host device based on the importance level of the logical disk. Furthermore, these control methods are control methods peculiar to a mirroring system for storing the same data on a plurality of magnetic disks. For example, a plurality of magnetic tape cartridges having different contents are mounted, and a plurality of tapes are simultaneously used by a plurality of drives. The present invention is not applicable to a magnetic tape library apparatus that executes read / write processing. The system described in Patent Document 3 sets priority according to the type of I / O instruction, and does not determine the processing order based on the priority of the medium.

  The present invention prevents processing delays to important volumes even when the load on the host interface is high, by performing priority processing of read / write requests for medium volumes with high priority depending on the load status of the host interface. An object of the present invention is to provide an information recording / reproducing apparatus and a control method thereof.

  The present invention relates to an information recording / reproducing apparatus including a plurality of medium drives capable of recording / reproducing processing in parallel with respect to a plurality of recording media, an instruction queue management unit for managing processing requests from a host device, and the recording medium Each of which is registered in the reference table according to need. The reference table in which the priority for each is registered, and a drive control unit that executes a processing request sent from the instruction queue management unit. The main feature is to operate in a priority mode in which the processing request is extracted based on the priority of each medium and sent to the drive control unit.

  The device of the present invention includes a load status determination unit that determines a load status of the device, and the instruction queue management unit determines that the load of the device is greater than or equal to a predetermined value by the load status determination unit. It is effective to operate in the priority mode.

  Further, in the priority mode, the instruction queue management unit preferentially takes out the processing request that is a read / write request and has a high priority for the target medium and sends it to the drive control unit. Is effective.

  Further, the instruction queue management unit manages the waiting time of the processing request from the host device, and when the waiting time of any processing request becomes equal to or greater than a predetermined value, the instruction queue management unit It is effective to take out the processing request and send it to the drive control unit.

  The apparatus further includes input / output means for the apparatus operator to register, change, or delete the priority for each medium in the reference table, or when a new medium is loaded in the medium drive It is effective to provide a priority information automatic registration means for reading the priority information recorded in the reference table and registering it in the reference table.

  The information recording / reproducing apparatus of the present invention can be configured as a magnetic tape library apparatus that performs read / write on one or more magnetic tapes selected from a library capable of mounting a plurality of magnetic tape cartridges.

  By setting the importance for each recording medium loaded in the library device and executing processing requests from the host device based on that importance, the influence of processing on other media being executed simultaneously can be avoided. Thus, it is possible to execute a processing request for a medium having high importance without delay.

  In addition, when the load status determination unit is provided and control is performed in the priority mode when the load status of the device exceeds the threshold, the load is distributed to each medium and the overall processing performance is improved during normal times when there is room in the device. At the same time, it is possible to prevent a processing delay to an important medium when the load is high.

  If priority processing is performed only for read / write processing requests in the priority mode, it is possible to avoid the inconvenience of processing low priority processing requests other than read / write even for important media. Can do.

  In addition, if the waiting time for each processing request is managed and priority processing is performed regardless of the medium priority when the waiting time exceeds a threshold, timeout of the processing request for a medium with low priority can be prevented. Can do.

  In addition, if the device operator is provided with input / output means for registering, changing, or deleting the priority for each medium in the reference table, the priority for each medium can be appropriately set for the convenience of the user. Further, when a new medium is loaded into the medium drive, the priority information recorded on the medium is read and registered in the reference table, so that the operator has to register the priority for each medium. Can be omitted.

  The best mode for carrying out the present invention will be described in detail below with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a magnetic tape library apparatus according to an embodiment of the present invention. Referring to FIG. 1, a host system (higher level device) 1 and a magnetic tape library device 2 are connected by a host interface 7, and the magnetic tape library device 2 includes a magnetic tape library control means 3 and a plurality of magnetic tape drives 4-4. 1 to 4-n, a magnetic tape transport device 5 and a magnetic tape storage 6 are provided. The host system 1 is, for example, a network system in which a plurality of computer terminals are connected, and a processing command specifying a magnetic tape volume is issued from each terminal to the magnetic tape library apparatus 1. Examples of the processing command include a medium transport command and a read / write command.

  The magnetic tape storage 6 can store a plurality of magnetic tape cartridges. In the example shown in FIG. 1, tape volume 1 is stored in cell # 0, tape volume 2 is stored in cell # 1, tape volume 3 is stored in cell # 3, and cell # 5. Tape volume 4 is stored, and cells # 2 and # 4 are empty. The magnetic tape library apparatus 2 has a plurality of magnetic tape drives 4-1 to 4 -n, and a plurality of drives can read / write a plurality of magnetic tapes in parallel. When there is a request from the host system 1, the designated tape volume is transported by the magnetic tape transport device 5 and loaded into one of the magnetic tape drives 4, where data is read / written.

  Processing instructions from the host system 1 are received by the magnetic tape library control means 3 via the host interface 7. Processing instructions for the magnetic tape transport device 5 are executed using the transport device interface 9, and processing instructions for the magnetic tape drive 4 are executed using the magnetic tape interface 8. An access line denoted by reference numeral 10 indicates a three-way access relationship between the magnetic tape stored in the magnetic tape storage 6, the magnetic tape devices 4-1 to 4-n, and the magnetic tape transport device 5. The host system 1, the magnetic tape drive 4, the magnetic tape transport device 5, and the magnetic tape storage 6 are well known to those skilled in the art and are not characteristic features of the present invention, so that a detailed description thereof is omitted.

  FIG. 2 is a block diagram showing the configuration of the magnetic tape library control means 3 which is a characteristic part of the present invention. Referring to this figure, the magnetic tape library control means 3 includes a tape drive control unit 31, a load status determination unit 32, a tape information management table 33, a tape device control unit 34, an instruction queue management unit 35, an instruction And an analysis unit 36.

  The command analysis unit 36 analyzes a processing command transmitted from the host system 1 via the host interface 7, and if the command is a tape transport system command, notifies the tape transport control unit 34 of the tape transport command 307, and sends the tape device system. In this case, the tape drive control unit 31 is notified of the tape device command 301. The tape transport control unit 34 receives a processing request for the tape transport system from the instruction analysis unit 36, and controls the magnetic tape transport device 5 using the transport device interface 9.

  When the tape drive control unit 31 receives the tape device command 301 from the command analysis unit 36, the tape drive control unit 31 notifies the load status determination unit of the current input / output status 302. The input / output status 302 indicates the status of an input / output command issued from the host interface 7, and includes a transfer capacity, the number of input / output commands, and the like. For example, the input / output status 302 includes the number of magnetic tape drives currently reading / writing, the transfer capacity assigned to each drive, and the like, so that the load on the host interface 7 can be determined. . The tape drive control unit 31 also receives command information 305 including the tape drive number and processing contents from the command queue management unit 35 and executes processing for the designated magnetic tape drive 4 using the magnetic tape interface 8.

  Based on the input / output status notified from the tape drive control unit 31, the load status determination unit 32 determines whether the control operation of the instruction queue management unit 35 is set to the normal mode or the priority mode, and the determination result 303 is displayed. The instruction queue management unit 35 is notified. Here, the normal mode refers to control for distributing the load equally to each tape drive 4, and the priority mode refers to control for distributing the load using the priority of the target magnetic tape volume. Say. In the present embodiment, the determination method of the load status determination unit 32 sets the priority mode if the load of the host interface 7 at that time has reached the upper limit of the processing capability, and sets the normal mode if not. Here, the determination method is not limited to this example, and the priority mode may be set if the load is a certain load or more.

  The instruction queue management unit 35 is a means for managing the order of processing requests in the tape drive control unit 31, and switches the operation mode according to the determination result 303 of the load status determination unit 32. In the normal mode, processing requests from the host system 1 are registered in the queue so that they are notified in order. In the priority mode, the tape management information table 33 is inquired about the priority of the target magnetic tape volume, and the processing request is registered in the queue corresponding to the priority of the magnetic tape volume. FIG. 3 shows an example of the tape management information table 33. In this table 33, the volume name of the magnetic tape mounted on the apparatus, the storage position (for example, cell number) in the magnetic tape storage 6, and the priority for each tape volume are registered. In this embodiment, the priority is set to three levels of low, medium, and high, and the instruction queue management unit 35 registers a processing request in the queue corresponding to this priority in the priority mode.

  The instruction queue management unit 35 extracts the processing request registered in the instruction queue as described above and sends the instruction information 305 to the tape drive control unit 31. At this time, in principle, the processing request is extracted from the processing requests registered in the high priority queue. In other words, when the priority is set to high, medium, or low, processing requests registered in the high priority queue are extracted first, and if there are no high priority queue processing requests, the medium priority queue processing requests are extracted. If there is no processing request for the middle priority queue, the processing request for the low priority queue is extracted and the command information 305 is notified to the tape drive control unit 31.

  The instruction queue management unit 35 according to the present embodiment further manages the waiting time of the processing request received by the tape drive control unit 31 in order to prevent a processing request from being timed out for a low-priority tape volume. When the waiting time exceeds a predetermined value, the processing request is taken out and sent to the drive control unit regardless of the priority of each medium.

  The priority of each tape volume is registered in the tape management information table 33 as shown in FIG. 3, and the priority information 304 of the target tape volume is reported in response to an inquiry from the instruction queue management unit 35. In this embodiment, as shown in FIG. 2, a tape management information input means 36 for registering, changing, or deleting the priority is provided in the library apparatus 2, and the operator sets the priority when the magnetic tape is loaded. Try to register. The tape management information input unit 36 includes an input device such as a keyboard and a mouse, and a display device such as a liquid crystal display that displays input information and registration information. Alternatively, the input unit 36 may be configured as a touch panel in which the display unit and the input unit are combined.

  The operation of the magnetic tape library apparatus 2 configured as described above will be described more specifically with reference to FIGS. FIG. 4 is a flowchart for explaining the operation until the processing request given by the host system 1 is registered in the instruction queue. First, when a processing request is given to the magnetic tape library device 2 by the host system 1, the command analysis unit 36 analyzes whether the command is for tape transportation or for the tape device (step S1). As a result, if it is an instruction for the tape device, the request is sent to the tape drive control unit 31 to determine whether it is a read / write request (step S2). If the request is a read / write request, the tape drive control unit 31 notifies the load status determination unit 32 of the current input / output processing status 302 (step S3). The load status determination unit 32 compares the notified input / output processing status 302 with the performance information of the host interface 7 that is held in advance, and sets the priority mode when the host interface 7 has reached the upper limit of the input / output processing capability. Otherwise, the normal mode is set, and the determination result 303 is notified to the instruction queue management unit 35 (step S4).

  When the priority mode is determined, the instruction queue management unit 3 refers to the magnetic tape management information table 33 to search the priority of the target magnetic tape (step S5), and confirms the priority information 304 (step S6). ). Then, the processing request is registered in the instruction queue corresponding to the priority obtained here. That is, in this embodiment, if the priority of the target tape volume is high, the processing request is registered in the high priority queue (steps S7 to S11), and if the priority is medium, it is registered in the medium priority queue (steps S8 to S9). If the priority is low, it is registered in the low priority queue (step S10).

  If the processing request of the host system 1 is not an instruction to the tape device, is not an instruction accompanied with read / write processing, or if the processing capacity of the host interface 7 is sufficient, the instruction queue management unit 3 makes a processing request in any case. Register in the priority queue.

  Next, processing request extraction or media drive execution processing by the instruction queue management unit 3 will be described with reference to FIG. As shown in FIG. 5, the instruction queue management unit 3 sequentially extracts processing requests with higher priority, and simultaneously manages the timeout time of each processing request. That is, if a process request is selected, if it is registered in the high priority queue, it is selected (step S20), and the process request time-out time registered in the low to medium priority queue having a lower priority than that is selected. If there is a processing request that has reached the maximum waiting time, the processing request is extracted with priority (steps S22 to S23). The medium drive control unit 31 is notified (step S24). Accordingly, the medium drive control unit 31 executes processing for the magnetic tape volume related to the command information 305.

  If there is no processing request in the high priority queue, the processing request registered in the medium priority queue is selected (step S21), the time-out time of the processing request registered in the low priority queue is confirmed (step S25), and waiting is performed. If no time has reached the maximum value, the command information 305 relating to the medium priority processing request is notified to the magnetic tape drive control unit 31 (step S26). If there is no processing request in the high-priority or medium-priority queue, the processing request in the low-priority queue is extracted and the command information 305 is notified to the magnetic tape drive control unit 31. In this case, there is no lower priority queue, so there is no need to check the timeout time of other processing requests.

  By managing the processing requests in this manner, the load on the apparatus is high without being affected by processing on other tape volumes that are being executed at the same time for read / write requests with high priority, that is, important tape volumes. Even in this case, processing delay can be prevented. In addition, the importance of each tape volume is managed in the magnetic tape library device, and the order of processing requests is determined on the device side. Therefore, priority is given to the host system without changing the I / O command specifications. Processing can be performed. That is, each time a processing request is issued on the host system side, priority information that can be recognized and processed by this magnetic tape library device does not need to be added to the processing request, and priority processing can be performed without setting the necessary specifications. Can be realized.

  At the same time as priority processing by importance for each magnetic tape medium, the waiting time of each processing request is managed, and processing is executed regardless of the priority of the medium for processing requests with long waiting time. Even when time management is performed, priority processing can be executed while preventing timeout.

  FIG. 6 is a block diagram showing the configuration of another embodiment of the apparatus according to the present invention. In this embodiment, each magnetic tape mounted in the library apparatus 2 has medium management information indicating the importance of the own tape, and when this is loaded into the magnetic tape drives 4-1 to 4 -n. It is configured to be read out and automatically registered in the tape management information table 33. That is, each magnetic tape is written with management information indicating importance in the tape head and / or periodically provided control information area, and each magnetic tape drive 4-1 to 4-n is loaded with a medium. When this is done, the management information 306 is read and notified to the tape management information table 33. The tape management information table 33 registers the management information 306 received from the magnetic tape drive 4.

  A registration example of the tape management information table 33 in the present embodiment is shown in FIG. As shown in FIG. 7, in the present embodiment, information indicating importance is added to the head of the tape volume name, the letter “H” attached to the head is high priority, “M” is medium priority, and “L” is The tape management information table 33 has columns for tape volume names and stored tape drive numbers. In the present embodiment, the constituent elements other than those described here are the same as those in the first embodiment described above, and detailed description of the configuration and operation of each element will be omitted.

  As described above, in this embodiment, since the importance of each medium is automatically registered in the management table 33 when the magnetic tape medium is loaded into the magnetic tape drives 4-1 to 4 -n, the operator of the apparatus. However, it is possible to save the trouble of manually registering the importance level for each medium. Further, as shown in FIG. 7, since the medium name including the importance is registered for each tape drive 4, it is sufficient to secure “the number of magnetic tape drives × the number of items” as the size of the tape management information table 33. For example, the table capacity can be reduced as compared with the embodiment of “the number of tape volumes loaded in the library apparatus × the number of items”.

  Further, as shown in FIG. 8 as another embodiment, the magnetic tape is not directly input from the magnetic tape drive 4 but is transferred from the magnetic tape drive 4 to the tape drive controller 31 by using the magnetic tape device interface 8 and then the magnetic tape. Management information 306 for each magnetic tape may be notified from the drive control unit 31 to the tape management information table 33.

  Although several embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be realized as various other embodiments. In particular, all of the embodiments described above relate to a magnetic tape medium library apparatus, but an information recording / reproducing apparatus configured to simultaneously read / write to some of a plurality of interchangeable recording media loaded therein. If so, the present invention is not limited to the magnetic tape, and the present invention can be applied to a library device of a replaceable recording medium such as a magnetic disk or an optical disk. The reference for switching the priority mode and the normal mode by the additional status determination unit 32 is not limited to the case where the load of the host interface 7 reaches the upper limit. For example, when the number of simultaneously driven magnetic tape drives exceeds a predetermined number. Other criteria can be used.

  Further, in the operation flowchart shown in FIG. 4, processing requests other than read / write and processing requests when there is a margin in the load on the host interface are registered in a queue having a medium priority. It is good also as a structure registered into this queue. Furthermore, in the above embodiment, the priority is set to three levels, but this may be two levels or four or more levels.

  The information recording / reproducing apparatus and the control method thereof according to the present invention perform priority processing of processing requests based on the priority for each medium without setting the priority for each processing request on the connected host system side, Since read / write commands for important media can be executed without being affected by other processes being executed simultaneously, processing delay can be prevented, so that read / write to a plurality of interchangeable recording media is performed simultaneously. It can be suitably used in the information processing industry.

1 is a block diagram showing a schematic configuration of a magnetic tape library apparatus according to an embodiment of the present invention. It is a block diagram which shows the structure of the magnetic tape library control means 3 shown in FIG. It is an image figure which shows the structural example of a magnetic tape information management table. It is a flowchart for demonstrating operation | movement of a magnetic tape library apparatus. It is a flowchart for demonstrating operation | movement of a magnetic tape library apparatus. It is a block diagram which shows the structure of the magnetic tape library control means concerning another Example of this invention. It is an image figure which shows another Example of a magnetic tape information management table. It is a block diagram which shows the structure of the magnetic tape library control means concerning another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Host system 2 Magnetic tape library apparatus 3 Magnetic tape library control means 4 Magnetic tape drive 5 Magnetic tape conveyance apparatus 6 Magnetic tape storage 7 Host interface 31 Tape drive control part 32 Load condition determination part 33 Tape management information table 34 Tape conveyance control part 35 Instruction queue management unit 36 Tape management information input means

Claims (10)

  In an information recording / reproducing apparatus including a plurality of medium drives capable of recording / reproducing processing in parallel with respect to a plurality of recording media, an instruction queue management unit that manages processing requests from a host device, and a priority for each recording medium And a drive control unit that executes a processing request sent from the instruction queue management unit, and the instruction queue management unit, for each medium registered in the reference table, if necessary. An information recording / reproducing apparatus that operates in a priority mode in which the processing request is extracted based on the priority and is sent to the drive control unit.   2. The information recording / reproducing apparatus according to claim 1, further comprising a load status determination unit that determines a load status of the device, wherein the instruction queue management unit has a load of the device equal to or greater than a predetermined value by the load status determination unit. The information recording / reproducing apparatus operates in the priority mode when it is determined.   3. The information recording / reproducing apparatus according to claim 1, wherein the instruction queue management unit is prioritized in the priority mode from among the processing requests that are read / write requests and that have a higher priority as a target medium. The information recording / reproducing apparatus is characterized in that it is taken out and sent to the drive control unit.   4. The information recording / reproducing apparatus according to claim 1, wherein the instruction queue management unit manages a waiting time for a processing request from the host device, and a waiting time for any processing request is equal to or greater than a predetermined value. In this case, the information recording / reproducing apparatus extracts the processing request and sends it to the drive control unit regardless of the priority of each medium.   5. The information recording / reproducing apparatus according to claim 1, further comprising an input / output unit for the apparatus operator to register, change, or delete the priority for each medium in the reference table. An information recording / reproducing apparatus.   5. The information recording / reproducing apparatus according to claim 1, wherein when a new medium is loaded on the medium drive, priority information recorded on the medium is read and registered in the reference table. An information recording / reproducing apparatus comprising a priority information automatic registration means.   7. The information recording / reproducing apparatus according to claim 1, wherein the apparatus reads / writes one or more magnetic tapes selected from a library capable of mounting a plurality of magnetic tape cartridges. An information recording / reproducing apparatus, which is a library apparatus.   In a control method of an information recording / reproducing apparatus including a plurality of medium drives capable of recording / reproducing processing in parallel with respect to a plurality of recording media, receiving a processing request from a host device and registering the processing request in an instruction queue management unit; A step of fetching a processing request by the instruction queue management unit and sending the processing request to the medium drive; and a step of executing the processing request by the medium drive; and a step of fetching the processing request by the command queue management unit is necessary And a processing request is extracted based on the priority of each recording medium loaded in the medium drive.   9. The control method according to claim 8, further comprising the step of monitoring the load of the information recording / reproducing device, and the step of fetching a processing request by the command queue management unit includes a load of the information recording / reproducing device equal to or greater than a predetermined value. A control request for an information recording / reproducing apparatus, wherein a processing request is extracted based on a priority for each recording medium. 10. The control method according to claim 8, wherein the step of receiving a processing request from the host device and registering it in the instruction queue management unit manages a waiting time for the processing request from the host device and the instruction queue management. The step of fetching the processing request in the unit extracts the processing request regardless of the priority for each medium when the waiting time of any processing request registered in the instruction queue management unit is equal to or less than a predetermined value. A control method for an information recording / reproducing apparatus.

Images