Patent Application
20080294748
1. Field of the Invention
The present invention relates generally to an improved data processing system and in particular to a method and apparatus for smoothing a transition between network file system versions. Still more particularly, the present invention relates to a computer implemented method, apparatus, and a computer usable program product for a proxy server between clients using network file system version three and servers using network file system version four protocol.
2. Description of the Related Art
A network file system provides transparent remote access to file systems. Thus, two computers connected over a network can access each other's files in memory or stored on a storage device. Sharing of files can be restricted such that only one computer can access the files of a second computer, or limitations can be placed on which files or directories can be accessed. An example of a network file system is NFS Version four™, available from Sun Microsystems. In this network file system, and on other advanced network file systems, a virtual file system is maintained to provide a path from a root node to exported file systems.
In general, a file system provides a file “map” for a data processing system such that the data processing system can find requested files. File systems for individual data processing systems are often preserved on a hard disk drive. A virtual file system is a file system that is a file “map” of one or more remote computers and/or one or more local computers, singularly or together. Thus, a virtual file system can be a file “map” for an entire network of computers. A virtual file system is therefore also a reflection of one or more physical file systems. A virtual file system is, currently, stored in volatile memory; often of a network file system server.
Network file system software, like most software comes in different versions. In the case of network file system software produced by Sun Microsystems, network file system version four has recently been published. Thus today, more and more businesses are implementing network file system version four; however, many businesses are still relying heavily on network file system version three. When businesses are ready to migrate to the new network file system version, the business has to change both servers and clients at the same time. This change can be troublesome because network file system version four protocol is not as mature as the protocol for network file system version three.
Several methods exist to smooth the transition between network file system versions. One method to smooth the transition is to setup the servers to serve both network file system versions at the same time, and then upgrade the clients one group at a time. However, with this method not all clients will receive the benefits network file system version four offers.
Exemplary illustrative embodiments provide for a computer implemented method, apparatus, and computer usable program code for transmitting data. In an illustrative method, transmission of the data is requested from a first data processing system to a second data processing system. The first data processing system uses a first network file system version and the second data processing system uses a second network file system version. A request is formed by requesting transmission of the data. The request is in a first protocol associated with the first network file system version. The request is received at a proxy server before transmitting the request from the first data processing system to the second data processing system. The request is converted at the proxy server to a second request. The second request is in a second protocol associated with the second network file system version. The second request is transmitted to the second data processing system and stored in a memory.
In another illustrative example, the second data processing system replies to the second request. A reply is formed in the second protocol. The reply is received at the proxy server before transmitting the reply from the second data processing system to the first data processing system. The reply is converted at the proxy server to a second reply in the first protocol. The second reply is transmitted to the first data processing system and stored in a memory.
In an illustrative example, the first network file system version is network file system version three and the second network file system is network file system version four. Additionally, the first data processing system can be capable of traversing across file systems, like a namespace of the second data processing system. Furthermore, the first data processing system can be capable of following network file system version four referrals through the proxy. The first data processing system can also be capable of performing workload balancing via a file system location command on the second data processing system. Moreover, the first data processing system can be capable of performing replication via a file system location command on the second data processing system. In a similar system, where the second file system uses a namespace concept, the proxy server can give out a unique file handle that represents each file system object within a namespace of the second data processing system.
In this case, the proxy server remaps an inode number that represents each file system object in each of a number of exported file systems to a unique number in the namespace of the second data processing system. Additionally or instead of this case, the proxy server can create a local file system, wherein the local file system corresponds to a file system of the first data processing system.
In still another illustrative example, the first protocol is a stateless protocol and the second protocol is a stateful protocol. In this case, the proxy server can handle state information on behalf of the first data processing system. In particular, the proxy server can handle state information by transmitting at least one of an open request and a close request to the second data processing system, wherein the first protocol is incapable of sending either the open request or the close request.
In yet another illustrative example, the illustrative method can include transmitting the open request. Responsive to waiting a time period during which no transmission activity occurs between the first data processing system and the second data processing system, the close request is transmitted.
The illustrative examples can also take the form of a means for requesting transmission of data from a first data processing system to a second data processing system. The means for requesting can be a data processing system, such as those described with respect to
In another illustrative example, the illustrative embodiments can be provided in the form of a system. The system includes a first data processing system. The first data processing system requests transmission of data from the first data processing system to a second data processing system. The first data processing system uses a first network file system version and the second data processing system uses a second network file system version. A request is formed by requesting transmission of the data. The request is in a first protocol associated with the first network file system version. The system also includes a proxy server connected to the first data processing system and the second data processing system via a network. The proxy server receives the request before the request is transmitted from the first data processing system to the second data processing system. The proxy server converts the request to a second request provided in a second protocol associated with the second network file system version.
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
In the depicted example, server 104 and server 106 connect to network 102 along with storage unit 108. In addition, clients 110, 112, and 114 connect to network 102. Clients 110, 112, and 114 may be, for example, personal computers or network computers. In the depicted example, server 104 provides data, such as boot files, operating system images, and applications to clients 110, 112, and 114. Clients 110, 112, and 114 are clients to server 104 in this example. Network data processing system 100 may include additional servers, clients, and other devices not shown.
In the depicted example, network data processing system 100 is the Internet with network 102 representing a worldwide collection of networks and gateways that use the Transmission Control Protocol/Internet Protocol (TCP/IP) suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, governmental, educational, and other computer systems that route data and messages. Of course, network data processing system 100 also may be implemented as a number of different types of networks, such as, for example, an intranet, a local area network (LAN), or a wide area network (WAN).
With reference now to
In the depicted example, data processing system 200 employs a hub architecture including a north bridge and memory controller hub (NB/MCH) 202 and a south bridge and input/output (I/O) controller hub (SB/ICH) 204. Processing unit 206, main memory 208, and graphics processor 210 are coupled to north bridge and memory controller hub 202. Processing unit 206 may contain one or more processors and even may be implemented using one or more heterogeneous processor systems. Graphics processor 210 may be coupled to the NB/MCH through an accelerated graphics port (AGP), for example.
In the depicted example, local area network (LAN) adapter 212 is coupled to south bridge and I/O controller hub 204 and audio adapter 216, keyboard and mouse adapter 220, modem 222, read only memory (ROM) 224, and universal serial bus (USB) and other ports 232. PCI/PCIe devices 234 are coupled to south bridge and I/O controller hub 204 through bus 238, and hard disk drive (HDD) 226 and CD-ROM 230 are coupled to south bridge and I/O controller hub 204 through bus 240. PCI/PCIe devices may include, for example, Ethernet adapters, add-in cards, and PC cards for notebook computers. PCI uses a card bus controller, while PCIe does not. ROM 224 may be, for example, a flash binary input/output system (BIOS). Hard disk drive 226 and CD-ROM 230 may use, for example, an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. A super I/O (SIO) device 236 may be coupled to south bridge and I/O controller hub 204.
An operating system runs on processing unit 206 and coordinates and provides control of various components within data processing system 200 in
Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as hard disk drive 226, and may be loaded into main memory 208 for execution by processing unit 206. The processes of the illustrative embodiments may be performed by processing unit 206 using computer implemented instructions, which may be located in a memory such as, for example, main memory 208, read only memory 224, or in one or more peripheral devices.
The hardware in
In some illustrative examples, data processing system 200 may be a personal digital assistant (PDA), which is generally configured with flash memory to provide non-volatile memory for storing operating system files and/or user-generated data. A bus system may be comprised of one or more buses, such as a system bus, an I/O bus, and a PCI bus. Of course, the bus system may be implemented using any type of communications fabric or architecture that provides for a transfer of data between different components or devices attached to the fabric or architecture. A communications unit may include one or more devices used to transmit and receive data, such as a modem, or a network adapter. A memory may be, for example, main memory 208 or a cache, such as found in north bridge and memory controller hub 202. A processing unit may include one or more processors or CPUs. The depicted examples in
Exemplary illustrative embodiments provide for a computer implemented method, apparatus, and computer usable program code for transmitting data across a network, such as network 102. In an illustrative method, transmission of the data is requested from a first data processing system to a second data processing system. The first data processing system uses a first network file system version and the second data processing system uses a second network file system version. A request is formed by requesting transmission of the data. The request is provided in a first protocol associated with the first network file system version. The request is received at a proxy server before transmitting the request from the first data processing system to the second data processing system. The request is converted at the proxy server to a second request. The second request is in a second protocol associated with the second network file system version. The second request is transmitted to the second data processing system. The second request is then stored in a memory.
The illustrative embodiments described herein can be implemented using a virtual file system, such as that shown in
Network file system 300 includes systems-calls interface 302. Systems-calls interface 302 is an interface through which a user can communicate requests to the network file system 300. For example, a user may request that a file be retrieved from a storage device of a remote data processing system. Likewise, systems-calls interface 302 can be used to perform a wide variety of operations with respect to a physical file system on a remote data processing system.
Systems-calls interface 302 communicates with virtual file system 304. Virtual file system 304 is maintained in a volatile memory of a data processing system. A virtual file system is a reflection of one or more physical file systems such as file systems 306. File systems 306 can be one or more potentially disparate file systems used by one or more potentially disparate operating systems. File systems 306 communicate with storage 308, which is a physical storage device containing one or more files and directories. File systems 306 can be used to look up files on storage 308.
Virtual file system 304 also communicates with network file system client 310. Network file system client 310 is a data processing system through which a user can access, retrieve, or otherwise manipulate a file in a remote data processing system. Network file system client 310 is used to support virtual file system 304. Network file system client 310 uses protocols 312 to communicate over a network 314 via a second set of protocols 316 that, in turn, allow communication with a second network file system server 318. Protocols 312 and 316 can be one or more of known protocols, such as remote procedure call (RPC) and/or external data representation (XDR). Network 314 can be any network such as network 102 shown in
Network file system server 318 communicates with virtual file system 320. Network file system server 318 supports virtual file system 320. Virtual file system 320 communicates with file systems 322 in a manner similar to the manner in which virtual file system 304 communicates with file systems 306. File systems 322 in turn communicate with storage 324. Storage 324 is in a remote geographical location compared to storage 308. Thus, systems-calls interface 302 can be used through network file system client 310 and network file system server 318 to access storage 324.
As described above, in a high availability environment in which one or more backup network file system servers exist, problems can arise when a changeover occurs from a primary network file system server to a backup network file system server. For example, performance degradation at the client can occur when volatile file handles are used. Additionally, loss of virtual file system information can occur.
The primary difference between network file 400 shown in
In an illustrative example, proxy server 402 acts as a network file system version three server to network file system client 310. At the same time, proxy server 402 also acts as a network file system version four client to network file system server 318. Thus, proxy 402 receives network file system version three requests submitted by network file system client 310 and translates the network file system version three requests into network file system version four requests. Proxy system 402 then transmits the network file system version four requests to network file system server 318.
If a reply is required or desired, network file system server 318 sends a network file system version four reply to proxy server 402. Proxy 402 then converts the network file system version four reply to a network file system version three reply. Proxy server 402 then transmits the network file system version three reply to network file system client 310.
In this manner, via proxy server 402, network file system client 310, which uses network file system version three, can enjoy all the benefits provided by network file system server 318, which uses network file system version four. For example, network file system client 310 will be able to traverse the namespace across file systems of network file system server 318. Additionally, network file system client 310 will be able to follow network file system version four through proxy server 402. Furthermore, network file system client 310 will be able to perform workload balancing versions via a fs_location (file system location) command through the proxy. This command is available through network file system version four. Additionally, network file system client 310 will be able to perform replication, via a fs_locations command, through proxy 402.
Additionally, the network file system architecture shown in
In the illustrative examples shown in
In the illustrative example shown in
When a network file system version three client request is received, proxy server 512 calls the appropriate VNOP calls to satisfy those network file system version three clients 506, 508, and 510. A “VNOP” is a function that operates on a vnode. A vnode, in turn, is a file system object, such as a file or directory. An example of a “VNOP” is a command for checking permission on a file or directory.
Because the export of the file system is a network file system version four mount, those VNOP calls are mapped into network file system version four requests. The network file system version four requests are sent network file system version four servers 514, 516, and 518 by the network file system version four client of proxy server 512. Once the network file system version four client receives the reply from network file system version four servers 514, 516, and 518, the network file system version four client will respond to the proxy VNOP calls based on the reply. Proxy server 512 then relays those responses back to network file system version three clients 506, 508, and 510.
In order to make network file system version four mounts exportable, proxy server 512 gives out a unique file handle that represents each file system object within the network file system version four namespace. Proxy server 512 can then access files across the file system boundary, as long as those file systems are within the network file system version four namespace exported by network file system version four servers 514, 516, and 518. proxy server 512 can export those file systems to network file system version three clients 506, 508, and 510 using network file system version three protocols. Thus, from the point of view of network file system version three clients 506, 508, and 510, all file systems are one giant file system.
In some illustrative examples, when using one giant file system and a network file system version three client, two file system objects can be encountered having the same inode number. To resolve this issue, proxy server 512 remaps the inode number that represents each file system object and each exported file system to a unique number in the exported network file system version four namespace. In one illustrative example, proxy server 512 creates a local file system corresponding to each network file system version three export on proxy server 512. Each file system object within the network file system version four namespace will have a corresponding file system object within that local file system. Thus, the inode number of the file system object in the local file system will be used to represent the file system object within the network file system version four namespace.
In this illustrative embodiment, network file system version four uses a stateful protocol. In a stateful protocol, information regarding transmission of replies and requests is maintained. Thus, for example, the fact that a given request to a reply has been transmitted between network file system clients and network file system servers is maintained. However, network file system version three is a stateless protocol. In a stateless protocol, information regarding requests and replies is not saved or stored. To accommodate this stateful feature, proxy server 512 handles state information on behalf of network file system version three clients 506, 508 and 510.
For example, protocols of network file system version three do not have “open” or “close” commands, due to the fact that network file system version three is stateless. However, a client of network file system version four protocol must send an open request to perform an input/output operation. Similarly, a client must send a close request after an input/output operation is complete.
Thus, when proxy server 512 processes a network file system version three read/write request from network file system clients 506, 508, or 510, proxy server 512 will send a network file system version four “open” request to network file system version four servers 514, 516, or 518. Once the read/write request is completed, proxy server 512 will send a network file system version four “close” request to network file system version four servers 514, 516, or 518. Thus, proxy server 512 can handle state information on behalf of network file system version three clients 506, 508, and 510, which otherwise would be unable to handle state information.
This process of handling state information can be improved. For example, proxy server 512 processes network file system version four “open” requests upon receiving a first input/output request from one or more of network file system version three clients 506, 508, and 510. However, proxy server 512 will not send network file system version four “close” requests to one or more of network file system version four servers 514, 516, and 518 until no input activity is detected at proxy server 512 for a predetermined period of time. The predetermined amount of time can be set by a user, determined automatically based on policies set by a user or manufacturer, or determined by any other means.
The process begins as a client using network file system version three protocols issues a request to a network file system version four server (step 600). A proxy server between network file system version three client and the network file system version four server converts the network file system version three requests to a network file system version four request (step 602). The proxy then transmits the network file system version four request to a network file system version four server (step 604). The network file system version four server then processes network file system version four request (step 606). The proxy server then determines whether an additional network file system version three request should be converted (step 608). If an additional network file system version three request is converted, then the process returns to (step 600) and repeats. Otherwise, the process terminates.
The process begins as a network file system version four server processes a received network file system version four request (step 700). The network file system version four server replies to a network file system version three client (step 702). A proxy server between the network file system version four server and the network file system version three client converts the network file system version four reply to a network file system version three reply (step 704). The proxy server transmits the network file system version three reply to the network file system version three client (step 706). The network file system version three client receives and/or processes the network file system version three reply (step 708). The proxy server then determines whether additional network file system version four replies should be converted (step 710). If additional network file system version four replies should be converted, then the process returns to (step 700) and repeats. Otherwise, the process terminates.
The process begins as a first data processing system requests transmission of data to a second data processing system, wherein the first data processing system uses a first network file system version and the second data processing system uses a second network file system version, wherein a request is formed by requesting transmission of the data, and wherein the request is in a first protocol associated with the first network file system version (step 800). The proxy server receives the request before the request is transmitted from the first data processing system to the second data processing system (step 802). The proxy server then converts the request to a second request, wherein the second request is in a second protocol associated with a second network file system version (step 804). The proxy server then transmits the second request to the second data processing system (step 806). In an illustrative embodiment, the second request can be stored in a memory of a corresponding network file system server. The memory can be either volatile memory, such as random access memory (ROM) or a stable memory, such as a hard disk drive.
Next, the network file system server replies to the second request thereby forming a reply in the second protocol (step 810). The proxy server receives the reply before the reply is transmitted from the second data processing system to the first data processing system (step 812). The proxy server then converts the reply to a second reply, wherein the reply is in the first protocol (step 814). The proxy server then transmits the second reply to the first data processing system (step 818). In an illustrative example, the network file system client stores the second reply in the memory (step 820). In an illustrative example, the memory can be a volatile memory, such as random access memory (ROM) or a stable memory, such as a hard disk drive.
The proxy server then determines whether an additional reply is received and needs to be converted (step 822). If an additional reply is to be received and converted then the process returns to (step 810) and the process repeats. Otherwise, the proxy server determines whether an additional request is to be received and converted (step 824). If an additional request is to be received and converted then the process returns to (step 800) and repeats. Otherwise, the process terminates.
The illustrative proxy server described herein can minimize the disruption caused by converting network file system clients using network file system version three protocols to network file system version four protocols. For example, network file system version three clients will be able to traverse a namespace across file systems of a network file system version four server. Additionally, the network file system version three clients will be able to follow network file system version four referrals through the proxy server. Additionally, the network file system version three clients will be able to perform workload balancing via a fs_locations command available in network file system version four through the proxy server. Additionally, network file system version three clients will be able to perform the replication via the fs_locations command available in network file system version four through the proxy server.
Thus, the proxy server is a network file system version four client to the network file system version four server, and the proxy server is a network file system version three server to a network file system version three client. Accordingly, the network file system version three clients can enjoy most or all of the benefits offered by network file system version four, through the use of the proxy server described herein.
The invention can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment containing both hardware and software elements. In a preferred embodiment, the invention is implemented in software, which includes, but is not limited to, firmware, resident software, microcode, etc.
Furthermore, the invention can take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by, or in connection with, a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer-readable medium can be any tangible apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The medium can be an electronic, magnetic, optical, electromagnetic, infrared, semiconductor system (or apparatus or device), or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid y state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and an optical disk. Current examples of optical disks include compact disk read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.
A data processing system suitable for storing and/or executing program code will include at least one processor coupled directly or indirectly to memory elements through a system bus. The memory elements can include local memory employed during actual execution of the program code, bulk storage, and cache memories, which provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution.
Input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening I/O controllers.
Network adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modems, and Ethernet cards are just a few of the currently available types of network adapters. description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
