The present invention relates to the art of storage control that transfers and stores files via communication networks.
Conventionally, storage systems composed of RAIDs (Redundant Arrays of Inexpensive Disks) in which multiple HDDs (Hard Disk Drives) are arranged in arrays for managing large amounts of data have been used.
These storage systems and host computers were mainly connected via block I/O interfaces such as FC (Fiber Channel) and SCSI (Small Computers System Interface) in which I/O are processed via block units.
The recent advancement in IT has lead to the development of inexpensive NAS (Network Attached Storage) file storage systems as disk array systems providing file services to clients by receiving file accesses from clients via the network. Typical examples of connection interface protocols of such systems are file I/O interfaces such as NFS (Network File Interface) and CIFS (Common Interface File System).
On the other hand, users such as companies and individuals have independently purchased hardware resources such as storage systems, servers and PC (Personal Computers) and software resources such as OS (Operating Systems) and AP (Application Software) to create their own systems.
However, the recent increase in the amount of data to be handled caused rapid rise of TCO (Total Cost of Ownership) of these systems, and the cutting down of costs has become an urgent task.
One method for solving this problem is the cloud computing system in which hardware and software resources are shared and used via communication networks such as the internet, and the use of such system is spreading widely. One example of use of such cloud computing system is disclosed in patent literature 1, which teaches using the system via the interne. The client must connect to the interne to use the cloud computing system.
Patent literature 2 discloses a prior art related to controlling the QoS (Quality of Service) of protocols from the viewpoint of user-friendliness (usability). The literature teaches a NAS storage system in which a priority set in a reply packet replied to the NAS client as an answer to a file access request for accessing a folder having a high level of importance is set higher than a priority set in the reply packet replied to the client as an answer to a file access request for accessing a folder having a low level of importance.
According to the prior art disclosed in the above-mentioned patent literature, the reading and writing of files from/to the cloud computing system must always be performed via the network. Therefore, there were delays in the data access and the access time was extended.
Therefore, as described, the files having high priority are stored in the NAS storage system while the files having low priority are stored in the cloud computing system. However, the capacity of files capable of being stored in the NAS storage system is limited. Therefore, if the used capacity exceeds a certain threshold, the files having relatively lower priority within the group of files having high priority must be transferred to the cloud computing system having a large capacity and deleted from the NAS storage system.
Further, if the client accesses a deleted file, the file must be rewritten into the NAS storage system from the cloud computing system. Therefore, the present invention aims at providing a file sharing service capable of answering to the needs of respective clients while preventing deterioration of performance of file accesses.
In order to solve the prior art problems, the present invention provides a file storage system having a local file system and connected to a communication network to which an archive system having a remotely controlled remote file system is connected, comprising:
a first communication interface system connected to said communication network;
a second communication interface system connected to a second communication network connected to a client terminal through which a client enters an access request which is a write request or a read request of a file; and
a processor for controlling the first communication interface system and the second communication interface system,
wherein the processor
(a) replicates a file in the local file system to the remote file system;
(b) manages the replicated file as a file to be stubbed;
(c) sets a priority information included in the access request as a priority information of metadata for managing the file in the local file system if the access from the client terminal is a first request;
(d) updates the priority information of the metadata based on a result computed from the priority information of metadata of an already stored file and the priority information of the access request if the access from the client terminal is a second request;
(e) retains an access date and time information of the access request in the metadata;
(f) monitors a used capacity of the local file system; and
(g) starts a deleting process of a file to be stubbed in the local file system using either the priority information or the date and time information in the metadata when the used capacity exceeds an upper limit set in advance.
The priority information included in the network packets transmitted from the clients are used to determine the priority of files to be stubbed (by which the actual data in the local file system is deleted and only the management information thereof is maintained). Therefore, the files being accessed frequently from networks having high priority will have higher priority and will not be deleted easily.
Furthermore, the access date information is also used as the condition for determining whether to perform stubbing, so the files having low priority but are new will not be deleted easily. The present system enables to provide a high speed file access system and service capable of responding to the demands of clients.
Now, the preferred embodiments of the present invention will be described with reference to the accompanied drawings.
First, the overall outline of the present invention will be described with reference to
The archive system communicates with a file storage system 20 connected thereto via a communication network (hereinafter referred to as network) 41 using an NIC (Network Interface Card) 103. The network can be either the internet using general public circuits or a LAN (Local Area Network).
The archive system is connected to a storage system 16 through an HBA (Host Bus Adapter) 104 and via a network (such as a SAN (Storage Area Network)), and performs accesses in units of blocks. The storage system 16 is composed of a controller 161 and disks 162. The disks 162 and 105 are disk-type memory devices (such as HDD (Hard Disk Drives)), but they can also be memory devices such as flash memories. The types of HDDs are selected according to use for example from FC, SAS (Serial Attached SCSI) and SATA (Serial ATA).
The storage system 16 receives an I/O request transmitted from the HBA 104 of the archive system 10. Upon receiving the I/O request, the controller 161 reads or writes (refers to) data from or to an appropriate disk 162. The archive system 10 and the storage system 16 constitute a core 1 acting as a collective base, such as a data center. It is also possible to adopt an arrangement in which the archive system is not connected to the storage system 16 (so that the core 1 is composed only of the archive system 10), and in that case, data is stored in the disks 105 of the archive system 10.
The file storage system 20 reads programs for controlling the whole system including the OS into a memory 202, and executes programs via a CPU 201.
Further, an NIC 203 performs communication between clients 30 and the archive system 10 connected via networks 41 and 60. The file storage system 20 is connected via an HBA 204 with the storage system 26 to access data. The storage system 26 receives an I/O request transmitted from the HBA 204 of the file storage system 20. Upon receiving the I/O request, a controller 261 writes data into or reads data from (refers to data in) an appropriate disk 262.
The file storage system 20 and the storage system 26 constitute a distribution base edge 2 as a remote office. Similar to the archive system 10, a configuration can be adopted in which the file storage system 20 is not connected to the storage system 26, and in that case, data is stored in the disks 205 of the file storage system 20.
The client 30 reads programs such as OS and AP (Application Programs) 310 stored in a disk 305 onto a memory 302, executes the program via a CPU 301, and controls the whole system. Further, the client performs communication via the network 60 with the file storage system 20 using an NIC303 in units of files. The disks 205, 262 and 305 adopt disk-type memory devices (HDD (Hard Disk Drives)), but they can also adopt memory devices such as flash memories. The types of HDDs are selected according to use for example from FC, SAS (Serial Attached SCSI) and SATA (Serial ATA).
Next, the software configuration of the whole system will be described with reference to
Further, the file transmission and reception function program 110 is a program for reading data from the disk 105 of the archive system 10 or the disk 162 of the storage system 16 in response to a transfer request from the archive function program 211 and transferring the read data to the file storage system 20.
A file system function program 112 is a program that relates the physical management units of the disks with the logical management units as files. The file system function program 112 enables reading and writing of data in file units to the archive system 10. The file system function program 312 of the client 30 also has a similar function.
Kernel/drivers 115, 215 and 315 are programs for executing control operations specific to hardware, such as the schedule control of multiple programs operating on the archive system 10, the file storage system 20 and the client 30 or hardware interruption processes.
The file storage system 20 includes a file system function program 212, similar to the archive system 10. Other than performing data read/write control, the file system function program 212 has a function to execute a priority determination process 2221, a file access notification process 2222 and a recall process 2223 which are characteristic to the present invention as shown in
A file sharing function program 213 is a program capable of enabling the client 30 to access files on the file storage system 20 via the network 60, and is equipped with an access request reception process function 2241 which is characteristic to the present invention. The file sharing function program 213 enables files to be shared among multiple clients.
A VLAN function program 214 is a function program for dividing a physical network 60 into virtual networks, and is equipped with a priority identification process function which is characteristic to the present invention.
The archive function program 211 is equipped with a replication process function 2211 for copying the files in the file storage system 20 to the archive system 10, and a stubbing (actual data of a file in the edge 2 is deleted and only the management information thereof is retained as shown in
Next, the outline of the operation of a stubbing control will be described with reference to
(P1) File_C is written from the client 30 to the file system 23 of the edge 20 (file storage system), and thereafter, File_B is written.
(P2) File_A is written from the client 30 to the file system 23 of the edge 20.
(P3) The files in edge 20 are replicated to the core 10 (archive system) (copies of files in edge 20 are created in the core 10) periodically (once a day). The files to be replicated are File_B and File_C. It is also possible to perform migration (according to which the files in the edge 20 are transferred to the core 10 and the files in the edge 20 are deleted) to realize stubbing.
(P4) The replicated files are not deleted but retained in the file system 23 of the edge 20. This status is called cache, enabling to provide an equivalent access performance as normal files (Cache_B, Cache_C).
(P5) When the used capacity of the file system 23 in the edge 20 exceeds a certain threshold (such as 90% of the total capacity of the file system), the files having old access dates are turned into stub files. In that case, the file to be stubbed is the Cache_C written first. The stub file retains only reference data to the file in the core, and does not retain any actual data (Stub_C).
(P6) When clients 31 through 34 access File_A and Cache_B in the edge 20, the data can be accessed at high speed since actual data exists in the edge 20. On the other hand, when the client 33 accesses Stub_C, since there is no actual data in the edge, the actual data must be downloaded from the core 10 to the edge 20 (recall process). In that case, the response time is extended by the recording process in the edge 20 and the accessing of the core 10.
Therefore, the system according to the present invention has the following characteristics.
(N1) The file storage system 20 of the edge 2 (including file systems 11, 12 and 13) provides a file sharing service using a VLAN (Virtual Local Area Network) function standardized by IEEE 802.1q. The file storage system 21 and 22 provides a similar function.
(N2) Priorities according to IEEE 802.1p are set to respective VLAN networks (according to which networks having larger numbers have higher priorities).
(N3) File_A is frequently accessed from VLAN: 10 (network 61) via virtual I/F 251 and NIC 24, Cache_B is frequently accessed from VLAN: 20 (network 62) via virtual I/F 252 and NIC 24, and Cache_C is frequently accessed from VLAN: 30 (network 63) via virtual I/F 253 and NIC 24.
(N4) The file storage system 20 identifies the priority included in the VLAN tag for each access, and determines the priority of the file being cached. According to
(N5) When the capacity of the file system has exceeded a certain threshold (90% of the total capacity), Cache_C having the lowest priority is stubbed first.
According to such configuration and operation of the whole system, the cache hit rate of client access is improved, and the provided service will have improved quality.
The actual operation will be described with reference to the drawings. First, the functional configuration of the whole system according to one preferred embodiment of the present invention will be described with reference to
The archive function 221 is composed of a replication process 2211, a stubbing process 2212, a list creation process 2213, and a recall process 2214, and in the list creation process 2213, a replication list 22131 and a stubbing list 22132 are created and updated.
The file system function 222 is composed of a priority determination process 2221, a file access notification process 2222, and a recall request process 2223. The file access notification process 2222 executes notification of an event when an access request or the like occurs. Upon receiving a recall request 226 generated via the recall request process 2223, data is rewritten from the archive system 10 to the file storage system 20 by the recall process 2214.
The file sharing function 223 includes an access request reception process 2231. The VLAN function 224 comprises a priority identification process 2241 and a VLAN packet transmission and reception process 2242 for transmitting and receiving tagged VLAN packets as shown in
Next, the actual operation will be described. First, the transmission and reception of packets will be described with reference to
Section a: A timing signal field for realizing synchronization (data length: 8 bytes)
Section b: MAC address of transmission destination (data length: 6 bytes)
Section c: MAC address of transmission source (data length: 6 bytes)
Section d: TPID (Tag Protocol ID) fixed to 0x8100 (2 bytes)
Section e: TCI (Tag Control Information) composed of the following tag control information (2 bytes).
e1) First 3 bits: Priority field. Priority value to be used by WEE 802.1p (CoS).
e2) Next 1 bit: CFI (Canonical Format Indicator) which indicates whether there is a routine information field or not.
e3) Last 12 bits: VID (Virtual LAN Identifier) which is a VLAN identifier from 1 to 4094.
Section f: Setting up the type (ID indicating the upper layer protocol to be stored in the data storage field (section g)).
Section g: Data storage field storing arbitrary data from 46 to 1500 bytes.
Section h: FCS (Frame Check Sequence). Frame error detection field (4 bytes).
The present invention uses the priority value stored in the priority field of section e1 (3 bits) to determine the order of stubbing.
At first, based on the settings information of the virtual I/F of the file storage system 20, a correspondence table of the IP address and VLAN_ID set for the virtual I/F is created (
Further, upon responding (transmitting) to the client, the virtual I/F as the transmission source is acquired using
Actually, if the IP address of the client of the transmission destination is 172.16.5.100/24, the virtual I/F belonging to the same network is eth. 40 from
The process performed at the time of reception of the tagged VLAN packet (2242 of
It is determined in step S083 whether the received packet is sent from a client or not, that is, whether the event is a client event or not. When the event is not a client event (No), it is determined that the event is an end event from a kernel/driver (S088), and the process is ended (S089).
If the event is a client event (Yes), the event is determined to be a packet reception event from the client, and packet reception (S085) is performed. Thereafter, a priority identification process as a subroutine (S086) for analyzing the received packet (corresponding to 2241 of
According to the priority identification process starting from S100 of
Next, whether or not the retrieved VLAN_ID exists in the VLAN_ID and priority correspondence table of
The priority Y computed from priority P1 stored in the packet when reference (reading)/writing is performed and priority P2 already stored in the file is stored in the metadata.
Y=Roundup ((P1+P2)/2) (Math. 1)
Y: Priority stored in the file
P1: Priority of the packet for reference/writing
P2: Priority stored in the file at the time of reference/writing
Roundup: Roundup function to an integer
Based on the above calculation, the files being accessed frequently from the network with high priority will have their priorities stored in the metadata gradually increased. Finally, the priority identification process is ended in step S109 and the procedure is returned to step S086. After returning, an access request event (S087) is transmitted (228 of
Next, the process during transmission of the tagged VLAN packet (2242 of
In step S093, it is determined whether the received packet is sent from a client or not, that is, whether the event is a client event or not. If the event is not a client event (No), the procedure determines that the event is an end event from a kernel/driver (S097), and the process is ended (S099).
When the request is a transmission request (Yes), the VLAN_ID is set (S094) based on the IP address of the transmission destination using the correspondence table of
As described, the priority of the file can be updated dynamically every time a packet is received from a client 30 (such as writing of a file) and a packet is transmitted to the client 30 (such as the reference (reading) of a file).
Next, the file sharing function (223 of
(11-1): Type of access to file (create new file, write, refer, delete)
(11-2): File name
(11-3): Data offset (start position of reference or writing)
(11-4): Data length (size of writing or reference data)
(11-5): Actual data (write data to be written)
(12-1): Result of received access request (success or failure)
(12-2): File name (storing reference file name)
(12-3): Data offset (storing start position of read data)
(12-4): Data length (storing read data size)
(12-5): Actual data (storing read data)
The priority of the file subjected to the access request is identified based on the transmission data (information of
The actual process flow of the access request reception process 2231 of the file sharing function 223 is illustrated in
At first, the contents of the received data (
Based on the executed result, the transmission data to the client is created based on
The file 151 stored in the file system has a structure illustrated in
The contents of the metadata are as follows.
(16-1): File creation date (recording the date when the file was created)
(16-2): Final access date (recording the final reference date of the file)
(16-3): Final update date (recording the final update date of the file)
(16-4): File status (recording the status of the file selected from normal/cache/stub)
(16-5): Reference to actual data (recording the reference to the actual data in the file storage system 20)
(16-6): Reference to file in the archive system 10 (recording the reference to the replicated file)
(16-7): Data synchronous flag
(16-8): Data delete flag
(16-9): Priority
The data synchronous flag discriminates whether the file stored in the archive storage system 10 must be synchronized with the file in the file storage system 20.
The data synchronous flag is turned ON when update (writing) of data occurs. In other words, when writing occurs in any of the states of status numbers ST2, ST6, ST10 or ST11, the data synchronous flag is turned ON. At this time, the status is transited from ST2 to ST4, from ST6 to ST8, or from ST10 and ST11 to ST13. The synchronous flag is turned OFF when replication is performed.
The data delete flag indicates whether or not to delete the actual data in the file storage system 20. The data delete flag is turned ON when a stubbed file is referred to from the client and a file is recalled from the archive system 10. At this time, when the actual data is deleted (re-stubbed), the data delete flag is turned OFF.
The priority corresponds to the value of the priority included in the tagged VLAN packet, and has a value from 0 to 7. Further, the value is updated to a value computed by Math. 1 every time the file is accessed, as mentioned earlier. In other words, the file being accessed frequently from networks having high priority will have their priorities stored in the metadata increased.
In
Next, the file access notification process 2222 will be described. When a file in the file system 23 is accessed, a notification of an event 225 as shown in
A “file creation event” is notified when the file operation 227 is “create new file” (No. 1 of
Further, the priority of a file is notified together with the event notification. File function processes for respective file accesses are described with reference to
Actually, the following steps are performed.
(20-1): Update the date information of No. 1 through No. 3 to current time.
(20-2): Set the file status of No. 4 to “Normal”, and the data synchronous flag of No. 7 and the data delete flag of No. 8 to “OFF”.
(20-3): The priority of No. 9 is updated to the priority notified by the file sharing function 223.
After step S202 is completed, a “file creation event” is notified to the archive function 221 (S203) as shown in No. 1 of
Next, the status of the file is determined (S213). If the file is in normal status, the writing is executed without any change (S2131). If the file is in cache status, writing of data (S2132) is performed, and the status of the data synchronous flag is confirmed (S2133). If the data synchronous flag is ON, step S214 is executed, and if the flag is OFF, a cache update event is notified to the archive function 221 (S2134), and thereafter, step S214 is executed.
If it is determined in S213 that the file is in stubbed status, the process executes in step S2135 the recall request process (
In step S214, the following steps are performed for the metadata of
(21-1): Update the final update date of No. 3 to the current time.
(21-2): Update the file status of No. 4, the data synchronous flag of No. 7 and the data delete flag of No. 8 according to the transition table of
(21-3): Update the actual data reference information of No. 5.
(21-4): Update the priority of No. 9 based on the result computed by Math. 1
Thereafter, the write request process is ended (S219). After ending the process, the procedure is returned to S144.
At first, the metadata of a file in the file system 23 and the metadata of the write file data are referred to (S221). The priority in the metadata and Math. 1 are used to compute the update priority (S222).
Next, the status of the file is determined (S223). If the file is in normal status, the writing (reference) of data is executed without any change (S2231). If the file is in cache status, writing (reference) of data (S2232) is performed as it is. If it is determined in S223 that the file is in stubbed status, the recall request process (
Next, the statuses of the data synchronous flag and the data delete flag are confirmed (S2235). If both flags are OFF (Yes), a stub reference event is transmitted (S2236) to the archive function 221, and thereafter, step S224 is executed. If the data synchronous flag or the data delete flag is ON, step S224 is executed without any change.
In step S224, the following steps are performed for the metadata of
(22-1): Update the final access date of No. 2 to the current time.
(22-2): Update the file status of No. 4, the data synchronous flag of No. 7 and the data delete flag of No. 8 according to the transition table of
(22-3): Update the actual data reference information of No. 5.
(22-4): Update the priority of No. 9 to the result computed by Math. 1
Thereafter, the reference request process is ended (S229). After ending the process, the procedure is returned to S144.
Next, the recall request process 2214 will be described. When a reference or read access occurs to a file in stubbed status, the data must be downloaded (rewritten) from the archive system. In this case, recalling (rewriting) of data is requested independently from event notification to the archive function 221.
If data exists (Yes), the recall request process is ended (S249). If data does not exist (No), the recall process S242 shown in
In the process of the recall process function 2214 of the archive function 221, at first, the metadata of the file subjected to the recall request is referred to (S251). Next, based on the reference information of the file in the archive system 10 in No. 6 of the metadata (
Next, we will describe the archive function 221. First, the list creation process 2213 monitors the event 225 notified from the file system function 222, and creates two kinds of lists, a replication list 22131 and a stubbing list 22132, in response to the notified event. The correspondence thereof is shown in
On the other hand, the stubbing list 22131 is created by assigning the date of occurrence of the event and the priority as the name of the list, as shown in
The flow of the list creation process is shown in
If the result of analysis is the reception of a file creation event (S2921), the reception of a cache update event (S2922) or the reception of a stub update event (S2923), the absolute path of the object file is recorded in the replication list of
If the result of analysis is the reception of a stub reference event (S2924), the current date is acquired (S294). The absolute path of the object file is recorded in the stubbing list having a name corresponding to the acquired date and the priority (S295). As described, the sequence of the list creation process is ended, and the process returns to monitoring the occurrence of an event notification 225.
Next, we will describe the process for replication (in which a copy of a file in the file system 23 of the file storage system 20 on the edge side is created in the archive system 10 on the core side). The present process is invoked periodically (once a day, for example) from the scheduling function of the kernel/driver 215, and the process shown in
(30-1): The replication list is sorted (S311 of
(30-2): Duplicated rows are deleted except for one row (S312).
(30-3): The metadata of the files are referred to in order from the top of the sorted list (S314) to determine whether the status number of
(30-4): The description of the object file is deleted from the replication list (S317).
(30-5): The processes of (30-3) and (30-4) are executed until the final file on the sorted replication list (S3139).
Next, the stubbing process will be described.
(32-1): Determine whether or not to execute the stubbing process (compare capacity with stubbing execution threshold value)
(32-2): Determine the list of objects to be stubbed (select the determination method of
(32-3): Determine the metadata of the file and execute redistribution thereof
(32-4): Execute stubbing (delete data section)
(32-5): Reconfirm the capacity of the file system 23 (compare capacity with stubbing restoration (stubbing suspension) threshold)
The present process is invoked periodically (for example, once every 30 minutes) from the scheduling function of the kernel/driver 215. The file storage system 20 checks the used amount of the file system 23, and when the amount exceeds a stubbing execution threshold (90% of the file system capacity), the stubbing operation is executed and continued until the used amount falls to or below a stubbing restoration threshold (80% of the file system capacity). Further, in order to use the file system efficiently and to prevent significant delay of the access processes, the stubbing execution threshold should be in the range of approximately 85% to 95% of the overall capacity, and the stubbing restoration threshold should be in the range of approximately 75% to 85% of the overall capacity.
First, the determination of the list of objects to be stubbed (selection of determination method of
The processing order thereof will be described with reference to
According to the present process in the order of date, at first, determination on whether to perform stubbing or not is performed in the oldest file group 3401 starting from those having the lowest priority “0” and working upwards toward priority “7” (so that the process is performed from the lower side of the arrow toward the upper side thereof). When the process of the file group 3401 is completed, then file group 3402 is subjected to determination, and thereafter, file groups 3403, 3404 and 3405 are sequentially subjected to determination on whether to perform stubbing or not. According to this method, the files having older dates are stubbed (deleted).
According to the method performed in the “order or priority” in No. 2 of
According to the method in the “order of ratio” in No. 3 of
Next, the overall operation of the stubbing process will be described with reference to
In
First, the stubbing method of
The contents of the process is to perform, to the files in the list of objects to be stubbed starting from the first file on the list, the determination of metadata and the redistribution process of the file (S386) and to determine whether or not the used amount of the file system after performing the process falls below a stubbing restoration threshold (S387). If this process is performed and the used amount of the file system becomes smaller than the stubbing restoration threshold (Yes), then the process is ended.
If the used amount does not become smaller than the stubbing restoration threshold, then the next file is subjected to metadata determination and redistribution process for similar determination. If the used amount does not becomes smaller than the stubbing restoration threshold even when all the files in one list of objects to be stubbed is subjected to metadata determination and redistribution process, then a similar process (S3850 to S3859) is performed to the next list of objects to be stubbed. As described, the lists of objects to be stubbed and the files in the lists are changed sequentially to perform the metadata determination and redistribution process until the used amount becomes smaller than the stubbing restoration threshold.
The detailed operation of the determination of metadata and redistribution process (S386) will be described with reference to
If both the date and the priority correspond (Yes), it is determined whether the status of the metadata (No. 4: file status, No. 7: data synchronous flag and No. 8: data delete flag of
If the access time and priority does not correspond to the name in the list in step S392 (No), the object file path is added to the last of the stubbing list to which the date and priority correspond (S397). Then, the object file path is deleted from the list of objects to be stubbed being currently processed (S398). When all the processes are ended (S399), the procedure returns to S386 of
Next, the sequence of operations from creating a new file to stubbing and reference of a file will be described with reference to
In
As shown in
As shown in
Next, as shown in
Thereafter, File_C 2013a is written in the file system 23, and at that time, the final access date and priority stored in the metadata are changed. The update of priority is computed via Math. 1 using the priority “2” and the priority “7” of the network to which the client in access is connected. In other words, (2+7)/2=4.5 is rounded up to “5”. This state is shown in
The above description has illustrated a replication process and a stubbing process, but the replication and stubbing operations can be performed simultaneously such as in a migration operation.
As described, the priority information included in the network packet is used for determining the priority of the file to be stubbed. Files being frequently accessed from networks having high priorities are prevented from becoming the object of stubbing (deleted), so that in other words, the files are constantly available in the file storage system and could be accessed at high speed.
Thus, the variety of networks (levels of priority) to which the clients are connected can be selected freely, and a high speed file access service responding to the demands of clients can be provided.
In the above-described embodiments, various information and data are referred to through drawing numbers or names of tables, but they are not restricted to such examples, and can be expressed in different ways. Further, the present system has been described as being composed of three components, which are the core (archive system), the edge (file storage system) and the clients (CIFS/NFS clients), but the system can also be composed of two components, which are an integrated core (archive system) and edge (file storage system) and the clients.
The present invention is applicable to information processing apparatuses and storage systems in general capable of accessing data via communication networks.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP11/04140 | 7/22/2011 | WO | 00 | 8/2/2011 |