JP4073775B2 - Cache built-in switch and recording medium recording program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cache built-in switch that connects a plurality of higher-level devices (servers or other computers that access disks) and a plurality of disks, and more particularly to a cache built-in switch that eliminates the need for cache synchronization between switches.
[0002]
[Prior art]
When connecting a large number of higher-level devices and a large number of disks, it is considered to use a connection switch in order to improve transaction performance and the like. There is a fiber channel switch as a standard for specific products of transmission lines and switches for connection. This fiber channel switch has an I / F for connecting to a host device and a disk, and converts data. FIG. 6 shows a conventional system using a fiber channel switch. This system includes a large number of host devices (represented by reference numeral 110) and a large number of disks (represented by reference numerals 180 and 190), and a number of connection switches 120, 130, 140, 150, 160, 170 is connected via a transmission line. The distance between each switch can vary from a short distance of several meters to a long distance of tens of thousands of meters.
[0003]
As shown in FIG. 6, the present invention assumes a system configuration in which one disk is directly connected to one switch and not directly connected to a plurality of switches (one disk is connected to a plurality of switches). Excludes system configurations that are directly connected). However, one switch may be directly connected to a plurality of disks (in the example shown in FIG. 6, the disk 180 is directly connected to only one switch 150 and the disk 190 is directly connected to only one switch 160. However, the switch 150 is directly connected to three disks, the switch 160 is directly connected to two disks, the switch 120 to two disks, the switch 130 to one disk, and the switch 140. Are directly connected to three disks and switch 170 is directly connected to two disks). Here, “direct connection” means a state where one disk is directly connected to a port of one switch, and “indirect connection” means that the switch and the disk are connected via different switches. The state that is.
[0004]
In the example shown in FIG. 6, when the host device 110 accesses the disk 180, it must go through one of the routes of the switches 120, 130, and 150 and the route of the switches 120, 140, and 150.
[0005]
Incidentally, a cache built-in switch in which a cache is built in the fiber channel switch has been proposed (see, for example, Patent Document 1). This built-in cache type switch has a cache control unit and cache management information for controlling the cache, and determines whether data exists in the cache (cache hit) and transmits data in response to a data request from a higher-level device. I do.
[0006]
In these conventional technologies, by enabling the cache of all the fiber channel switches, each host device can access data on the disk at high speed.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-325207
[Problems to be solved by the invention]
However, if the caches of a plurality of switches are enabled as in the prior art, the cache of the switch directly connected to the disk is updated in order to update the data of a specific disk in a specific upper device. When this data is updated, it is necessary to synchronize the cache contents of all other switches. In order to synchronize, it is necessary to notify all other switches of the modifications that occurred in the cache of a specific switch. The traffic for this notification increases in proportion to the number of switches, causing a problem of traffic pressure.
[0009]
The present invention has been made in view of the above problems, and it is an object of the present invention to eliminate the synchronization of caches of the respective switches and to reduce traffic pressure.
[0010]
[Means for Solving the Problems]
The invention according to claim 1
A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. The cache built-in type switch includes a direct connection disk detection unit, a direct connection disk table, a cache information control unit, a cache memory, and a path switching unit. The disk number, which is information for identifying the disk directly connected to itself, is held, and the directly connected disk detection unit detects the disk directly connected to the cache built-in switch, and determines the disk number of the disk. Register in the directly connected disk table and The information control unit determines whether or not the destination disk number recorded in the received frame is stored in the directly connected disk table, and if so, caches the destination disk. By enabling the control to be invalidated and invalidated when not stored, information that identifies the disk directly connected to itself is used to directly connect to the cache memory held by itself. It is characterized in that it is controlled not to hold data of a disc that is not directly connected to itself while it is controlled so as to be able to hold data of a disc .
[0011]
The invention according to claim 2
A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. It holds the disk number, which is information that identifies the disk that is directly connected to itself, and uses the information that identifies the disk that is directly connected to itself to store it in its own cache memory. A disk that is directly connected to the switch is connected to a switch with a built-in cache that controls data so that it can retain data of a disk that is directly connected, but not to retain data of a disk that is not directly connected to itself. To determine whether or not the disk is directly connected, the disk is directly connected When it is determined that, characterized by recording a direct connection detection processing program for executing the procedure for registering the disk number of the disk to direct connections disk table.
[0012]
The invention according to claim 3
A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. It holds the disk number, which is information that identifies the disk that is directly connected to itself, and uses the information that identifies the disk that is directly connected to itself to store it in its own cache memory. Controls so that the data of the disk that is directly connected can be held, while the switch with the cache built-in switch that controls not to hold the data of the disk that is not directly connected to itself. Number acquisition procedure, the disk number is directly connected disk table When it is determined that the disk is stored, the procedure for enabling the cache when accessing the disk, and when it is determined that the disk number is not stored in the directly connected disk table, the disk is accessed. Then, a valid / invalid processing program for executing a procedure for performing processing for invalidating the cache is recorded .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The cache built-in switch according to the present invention will be described below with reference to FIGS. 1 shows a configuration of a cache built-in switch according to the present invention, FIG. 2 shows a flowchart of direct connection detection processing of a direct connection disk detection unit, FIG. 3 shows an example of a direct connection disk table, and FIG. 4 shows a cache information control unit. FIG. 5 is a diagram showing an example of a system state when the cache built-in switch according to the present invention is operated. FIG. 1 shows only the host device 110, the switches 120, 130, 140, 150, and the disk 180 with the reference numerals extracted from FIG. 6 of the prior art.
[0014]
In FIG. 1, the switch 150 includes a direct connection disk detection unit 151, a direct connection disk table 152, a cache information control unit 153, a cache memory 154, and a path switching unit 155. The switches 120, 130, 140, 160, and 170 have the same configuration. In FIG. 1, the switch 150 is directly connected to the disk 180 and is indirectly connected to the host device 110 via the switches 130 and 120 or via the switches 140 and 120. The cache memory 154 stores the contents of the cache, and the path switching unit 155 switches the path between the switches 130 and 140 and the disk 180 and is conventionally known.
[0015]
The directly connected disk detection unit 151 detects the disk 180 directly connected to the switch 150, and the disk number of the disk 180 (an identifier for identifying each disk. For example, in the fiber channel, WWN (WWN is a device number). The identification number of each disk) is registered in the directly connected disk table 152. FIG. 2 shows a flowchart of this direct connection detection process.
[0016]
In FIG. 2, the direct connection disk detection unit 151 is a direct connection detection processing program triggered by a power-on or reboot of the switch 150, a connection between the switch 150 and the disk 180, a power-on or reboot of the disk 180, or an external command. Start up. First, it is determined whether or not the disk to be directly connected to the switch 150 is directly connected (step S201). If the disk is not directly connected, the direct connection detection process is terminated. When it is determined that the disk is directly connected, the disk number of the disk 180 is registered in the directly connected disk table 152 (step S202), and the direct connection detection process is terminated.
[0017]
When the connection between the switch 150 and the disk 180 is adopted as an opportunity to start the direct connection detection processing program, for example, in the fiber channel, the disk 180 performs fabric login (FLOGI) or N_Port login (PLOGI) to the name server of the switch 150. The timing may be used. Alternatively, the connection of the disk 180 can be detected by periodically monitoring the port of the switch 150.
[0018]
In order to obtain the disk number of the disk 180 directly connected to the switch 150, for example, in the fiber channel, it is performed as follows. First, the WWN of the device directly connected to the switch 150 is acquired by a GA_NXT (Get all next) command. Next, the device type of each WWN is confirmed by a GPLT (Get Platform Type) command. By combining the above information and determining which of the directly connected devices is the disk, the WWN of the directly connected disk is acquired.
[0019]
The direct connection disk table 152 is a table for registering the disk numbers of the disks directly connected to the switch 150 as described above. FIG. 3 shows an example of the direct connection disk table 152. The direct connection disk table 152 stores the disk 180 directly connected to the switch 150 and the disk numbers of other disks (for example, No. 1, No. 5, No. 8).
[0020]
Note that the direct connection disk table 152 of the present invention erases all registered disk numbers when the switch 150 is powered on or rebooted, and disconnects the disk from the switch 150 or is directly connected to the switch 150. When the power of the disk is turned off, only the disk number of the disk is erased. Therefore, the disk number of the disk that was previously connected directly to the switch 150 but is not directly connected is the directly connected disk. There is no such thing as being stored in the table 152.
[0021]
The cache information control unit 153 determines whether or not the destination disk number recorded in the received frame is stored in the direct connection disk table 152, and enables / disables the cache for the destination disk. It performs control related to conversion. FIG. 4 shows a flowchart of the cache valid / invalid process.
[0022]
In FIG. 4, the cache information control unit 153 activates a cache validity / invalidity processing program triggered by frame transmission / reception. First, the destination disk number is acquired from the received frame (step S401). Next, it is determined whether or not the acquired disk number is stored in the directly connected disk table 152 (step S402). When it is determined that the disk number is stored in the directly connected disk table 152, the disk number In access to, after processing for validating the cache (step S403), the cache valid / invalid process is terminated. If it is determined that the disk number is not stored in the directly connected disk table 152, the cache valid / invalid process is terminated after performing a process for invalidating the cache for accessing the disk (step S404).
[0023]
FIG. 5 is a diagram showing an example of the system state when the cache built-in switch of the present invention is operated.
[0024]
A host device 110 that uses the disk 180 and the disk 180 are connected by a plurality of switches 120, 130, 140, and 150 via a fiber channel. As shown in FIG. 5, since the switches 120, 130, and 140 are not directly connected to the disk 180, the cache is invalidated when accessing the disk 180. On the other hand, since the switch 150 is directly connected to the disk 180, the cache for input / output to the disk 180 is validated.
[0025]
As described above, by operating the cache information control unit 153 of the switch 150, the cache of the switch 150 is automatically automatically accessed only for the access from the host device to the disk 180 directly connected to the switch 150. The cache of the switch 150 is automatically invalidated for accesses from higher-level devices to other disks indirectly connected to the switch 150. In other words, in a configuration in which multiple higher-level devices and multiple disks are connected via multiple switches, only the switch that is directly connected to that disk is the cache that is valid for accessing a specific disk. There is only one.
[0026]
By doing so, since the cache for temporarily storing the data contents of one disk is for one switch, it is not necessary to synchronize data among a plurality of switches. Therefore, it does not cause traffic pressure due to synchronization.
[0027]
In addition, in order to control cache enable / disable in a plurality of switches, information on which disk is directly connected to which switch is necessary. Because this information is collected automatically, the amount of work can be reduced.
[0028]
Also, when a host device updates the data contents of a disk, it always writes to the cache built in the switch directly connected to the disk, so it always switches over the data contents of the disk. The contents of the cache are newer. Therefore, the reason for reflecting the contents of the switch cache to the disk is limited to when the switch powers off and when the cache memory capacity is insufficient and it is necessary to write back to the disk. Traffic between the disks can be reduced.
[0029]
【The invention's effect】
As described above, according to the present invention, in a system in which a plurality of host devices are connected to a plurality of disks via a plurality of cache built-in switches, only the cache of the switch directly connected to the disk is automatically used. By enabling the switch, it is possible to eliminate the synchronization of the caches of the respective switches and to reduce the traffic pressure.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a switch with a built-in cache according to the present invention.
FIG. 2 is a flowchart of direct connection detection processing of a direct connection disk detection unit 151.
FIG. 3 is a diagram showing an example of a direct connection disk table 152;
FIG. 4 is a flowchart of a cache valid / invalid process performed by a cache information control unit 153;
FIG. 5 is a diagram showing an example of a system state when the cache built-in switch of the present invention is operated.
FIG. 6 is a diagram showing a conventional system using a cache built-in switch.
[Explanation of symbols]
110 Host device 120 Switch 130 Switch 140 Switch 150 Switch 151 Directly connected disk detector 152 Directly connected disk table 153 Cache information controller 154 Cache memory 155 Path switching unit 160 Switch 170 Switch 180 Disk 190 Disk

Claims (3)

A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. Because
The cache built-in switch includes a direct connection disk detection unit, a direct connection disk table, a cache information control unit, a cache memory, and a path switching unit.
The cache built-in switch holds a disk number that is information for identifying a disk directly connected to itself, and the direct connection disk detection unit detects a disk directly connected to the cache built-in switch, The disk number of the disk is registered in the directly connected disk table, and the cache information control unit determines whether or not the destination disk number recorded in the received frame is stored in the directly connected disk table. Using information to identify the disk directly connected to itself by enabling the cache for the destination disk if it is stored and invalidating it if it is not stored , Keep the data of the disk directly connected to itself in the cache memory While controlling the so that, controlled not to hold data of a disk that is not connected itself directly, the cache built-in switch, characterized in that. A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. It holds the disk number, which is information that identifies the disk that is directly connected to itself, and uses the information that identifies the disk that is directly connected to itself to store it in its own cache memory. The disk that is directly connected to the switch is connected to the switch with a built-in cache that controls the data of the disk that is not directly connected to the cache, while controlling the data so that the data of the disk that is directly connected can be retained. To determine whether or not the disk is directly connected, the disk is directly connected When it is determined that a direct connection detection processing program computer-readable recording medium characterized by recording a for procedures, to the execution of registering the disk number of the disk to direct connections disk table. A cache built-in switch in a system in which a plurality of cache built-in switches are connected to each other, and when a disk is connected to the cache built-in switch, at least one cache built-in switch is directly connected simultaneously. It holds the disk number, which is information that identifies the disk that is directly connected to itself, and uses the information that identifies the disk that is directly connected to itself to store it in its own cache memory. Controls so that the data of the disk that is directly connected can be held, while the switch with the cache built-in switch that controls not to hold the data of the disk that is not directly connected to itself. Number acquisition procedure, the disk number is directly connected disk table When it is determined that the disk is stored, the procedure for enabling the cache when accessing the disk, and when it is determined that the disk number is not stored in the directly connected disk table, the disk is accessed. A computer-readable recording medium having recorded therein a valid / invalid processing program for executing a procedure for performing processing for invalidating a cache .

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