US 20060026263 A1
A method and system for managing stored data on a computer network organizes data into logical volumes, and each logical volume has a friendly name associated with it. A domain controller keeps track of the friendly names of the logical volumes and associates those friendly names with the actual physical paths of the logical volumes. When a client computer on the network wishes to access a logical volume, it sends a look-up request having the friendly name to the domain controller. The domain controller may fulfill the request by sending the path of the logical volume to the client computer.
1. A method for managing stored data on a computer network, the computer network comprising at least a first, a second, and a third node, the first node comprising a server, the second node comprising a storage device, and the third node comprising a client computer, the method comprising:
the server computer receiving, from the client computer, a request for the path of a logical volume stored on the computer network, the request including a name of the logical volume;
the server computer referencing a data structure comprising an association between the name of the logical volume and a path of the logical volume; and
the server computer providing the path to the client computer, thereby permitting the client computer to access the logical volume via the computer network.
2. A computer-readable medium having stored thereon computer-executable instructions for performing the method of
3. The method of
the server computer determining whether the client computer is permitted to have access to the logical volume; and
the server computer performing the providing step based on the determining step.
4. The method of
5. The method of
6. The method of
7. The method of
locating the name of the logical volume in the data structure;
determining the identity of a storage device on the network that is responsible for and maintaining the logical volume; and
determining which logical unit number of the storage device corresponds to the logical volume,
wherein the providing step comprises transmitting, to the client computer, the identity of the storage device and the logical unit number.
8. The method of
locating the world-wide name of the logical volume in the data structure; and
determining the identity of a storage device on the network that is responsible for maintaining the logical volume,
wherein the providing step comprises transmitting, to the client computer, the identity of the storage device and the world-wide name of the logical volume.
This is a Divisional of U.S. patent application Ser. No. 10/164,950, titled “METHOD AND SYSTEM FOR MANAGING STORED DATA ON A COMPUTER NETWORK”, filed Jun. 06, 2002, which is hereby incorporated herein.
Name services have been in use on computer networks for many years. In general, the main function of a name service is to map a name, such as a file name, or network domain name, to some arbitrary data record, such as a file or a network address. A name service can, for example, receive a “look-up request” that includes a name, such as a textual name of a web site, from a requesting client and return information associated with the name, such as the IP address of the web site, to the requesting party. One of the most popular name services in use today is the Domain Naming Service (DNS).
One function of a name service is to define a namespace for computers on a network that is independent of the physical addresses used by the network. For example, if the website www.foo.com changes its IP address from 184.108.40.206 to 220.127.116.11, the website simply registers the change with the nearest DNS server. The DNS server responds by de-associating www.foo.com from the IP address 18.104.22.168 and creates a new association between www.foo.com and 22.214.171.124. Thus, the rest of the world remains unaware that there was ever any change, and continues to type www.foo.com in their web browsers and achieve the desired result of reaching the website.
A data storage device, such as a magnetic disk drive, can be coupled to or integrated with an individual computer on a network and, therefore, can effectively have its own IP address and participate in a name service such as DNS. However, data storage technology has become increasingly sophisticated. With the proliferation of storage networks, such as so-called Storage Area Networks (SAN), multiple computer systems can now be connected to networks of multiple data storage devices. Although efforts have been made to create a DNS-like naming system for Internet storage systems [see, for example, the Internet Storage Name Service (iSNS), which is documented in various Internet Engineering Task Force (IETF) drafts], there is currently no effective way for a data storage device to divide its computer-readable media (its magnetic disks, for example) into logical volumes and to have each of those volumes be recognized as a separately addressable entity in a name service. Also, there is currently no effective way to build a SAN name space that makes the physical location of a storage device transparent to computer systems that need to access the storage device.
The invention is generally directed to a method and system for managing stored data on a computer network, in which the data is organized into logical volumes, and each logical volume has a friendly name associated with it. A logical volume may correspond to an individual computer-readable storage element or to a multiple storage elements. For example, a logical volume can represent a single spindle (a physical hard disk), an entire disk array, or a logical partition of a disk array. A domain controller keeps track of the friendly names of the logical volumes and associates those friendly names with the actual physical paths of the logical volumes. When a client computer on the network wishes to access a logical volume, it sends a look-up request, which includes the friendly name, to the domain controller. The domain controller may fulfill the request by sending the path of the logical volume to the client computer.
Additional features and advantages of the invention will be made apparent from the following detailed description of illustrative embodiments that proceeds with reference to the accompanying figures.
While the appended claims set forth the features of the present invention with particularity, the invention, together with its objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which:
Prior to proceeding with a description of the various embodiments of the invention, a description of the computer and networking environment in which various embodiments of the invention may be practiced will be provided. Although it is not required, the present invention may be implemented by program modules that are executed by a computer. Generally, program modules include routines, objects, components, data structures and the like that perform particular tasks or implement particular abstract data types. The term “program” as used herein may connote a single program module or multiple program modules acting in concert. The invention may be implemented on a variety of types of computers. Accordingly, the terms “computer,” “device,” and “computing device” as used herein include personal computers (PCs), hand-held devices, multi-processor systems, microprocessor-based programmable consumer electronics, network PCs, PC servers, minicomputers, mainframe computers and the like. The invention may also be employed in distributed computing environments, where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, modules may be located in both local and remote memory storage devices.
An example of a networked environment in which the invention may be used will now be described with reference to
Computing device 100 may also contain communications connections that allow the device to communicate with other devices. A communication connection is an example of a communication medium. Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. The term computer readable media as used herein includes both storage media and communication media.
Computing device 100 may also have input devices such as a keyboard, mouse, pen, voice input device, touch input device, etc. Output devices such as a display 118, speakers, a printer, etc. may also be included. All these devices are well known in the art and need not be discussed at length here.
The invention is generally directed to a method and system for managing stored data on a computer network, in which the data is divided up into logical volumes, and each volume is separately addressable via a name service. Each logical volume may correspond to an individual computer-readable storage element, such as a disk, or may be stored across multiple storage elements. As the physical location of a volume changes, its physical location can be re-registered with the name service. Thus, devices on the computer network can continue to access the volume via the name service using the volume's “friendly” name. In various embodiments of the invention, the name service can maintain security of the data on the network by restricting the ability of devices on the network to resolve the friendly names of logical volumes into physical paths.
Various embodiments of the invention will now be described in the context of an example network, shown in
The logical volume examples of
The registration message contains a unique identifier, such as a world-wide name, that uniquely identifies the storage device 158. The registration message also includes the identification number and the path of the logical volume on the storage device. If the storage device 158 is a SCSI device, the logical volume may be identified in the registration message by its logical unit number (LUN). The logical volume may also be identified by a world-wide name. As used herein, the term “world-wide name” refers to an effectively unique number of reasonably large size (256 bits, for example). The registration message may also contain additional information, such as the characteristics of the storage device 158 or its location on the topology of the network 150 and the path needed to access it. The request message can also provide information such as a Public/Private Key pair for authorization or for encryption of the channel over which communication with the storage device 158 is taking place.
When the domain controller 154 receives the registration message, it initiates the process of assigning a name to the logical volume 174. In doing so, the domain controller 154 references a data structure 157 to determine whether the storage device 158 has ever registered with the domain controller 154 before. In determining whether the storage device 158 has previously registered, the domain controller 154 may require the storage device 158 to authenticate itself. For example, the domain controller 154 may ask the storage device 158 for a security key, a hash of a certain key value, or a hash of a network attribute in order to verify that the storage device 158 had, in fact, previously registered. If the domain controller 154 determines that it has, then the domain controller 154 may simply continue the naming system previously used with the storage device 158. Otherwise, the domain controller 154 establishes a new naming system for volumes on the storage device 158.
If required, a name is generated for the logical volume 174. The name may be generated in a variety of ways. For example, the domain controller 154 itself may generate the name automatically. Alternatively, a human administrator could choose the name. The name that is chosen for the logical volume 174 may be completely arbitrary, or may convey data concerning the logical volume. For example, the logical volume may be named Finance_vol—1_DataCenter—5_RAID_unit—3” to indicate that the volume is one that is intended to store data generated by the finance department, is the first volume used in that department, and is physically located in Data Center 5 on RAID (Redundant Array of Independent Disks) unit 3. The domain controller 154 then enters the name, referred to hereinafter as the “friendly name,” into the data structure 157 and associates the friendly name with the identification number of the storage device 158, and with the path and world-wide name of the logical volume 174. At some point during, or after, the registration process, the domain controller 154 may send a message to the storage device 158 to acknowledge receipt of the registration message or to confirm registration of the logical volume 174. The domain controller 154 may also send other information to the storage device 158, such as an Access Control List (ACL) that identifies which computer systems are permitted to access the storage device 158.
According to various embodiments of the invention, users or programs wishing to obtain access to particular logical volumes stored on a network are required to pass through one or more security checks. These security checks may be enforced by the domain controller 154 of
In the previous example, the domain controller may, in addition to the procedures described, publish certain storage devices and/or logical volumes. In this way, the computer systems that do not have physical access to the storage devices and/or logical volumes can learn about them and automatically modify their network topologies or connections to gain access to them.
The SAN domain controller 206 executes several program modules, including a security module 218 for authenticating hosts and controlling access to storage devices on the storage area network 202, a discovery module 220 for enabling storage devices on the storage area network 202 to be automatically recognized by the SAN domain controller 206, a LUN management module 222 for keeping track of the logical unit numbers of various logical volumes on the storage area network 202 and a name space management module 224 for keeping track of how friendly names are mapped to network paths for the various logical volumes on the network. The SAN domain controller 206 also executes a SAN provider API module 230, which allows the SAN domain controller 206 to communicate with various storage devices on the storage area network 202. The SAN provider API module 230 abstracts the specifics of each storage device so that the domain controller 206 can communicate with each storage device using a single, common language. The SAN domain controller 206 executes a server-side SAN API module 216 for communicating with clients, such as host computers. Although the SAN domain controller 206 is depicted as a single unit in
The SAN domain controller 206 executes a first storage provider module 232 and a second storage provider module 234 for communicating with the different storage providers made by different manufacturers. Examples of storage providers include switches, disk arrays, so-called JBODs (“just a bunch of disks”), tape libraries and juke boxes. For example, in
An example of how the SAN domain controller 206 manages the logical volume 244 (
To write and read data to and from the first logical volume 244, for example, the host computer 204 first registers with the SAN domain controller 206, if it has not already done so in the past. It does this by sending a registration message to the SAN domain controller 206 (Arrow D). The registration message includes a request to attach to the SAN, as well as the host computer's authorization credentials (if needed). The security module 218 then executes a security procedure to determine whether the host computer 204 should be permitted to be registered. For example, the security module 218 may determine whether the host computer 204 has authorization to access the SAN 202 and which pieces of hardware the host computer 204 is permitted to access. If the SAN domain controller 206 accepts the registration request, it responds with an acknowledgment message to the host computer 204 (Arrow E). The SAN domain controller 206 then creates a virtualization (a directory tree, for example) of the resources that the host computer 204 is permitted to access, and provides the virtualization to the host computer 204. Once the host computer 204 registers, it can then attempt to access the first logical volume 244. To do so, the host computer 204 determines the friendly name of the first logical volume 244. It may do this by searching a well-known directory located on the LAN 200. The host computer 204 then sends a look-up request to the SAN domain controller 206. The look-up request includes the friendly name of the first logical volume 244 (Arrow F). The security module 218 of the SAN domain controller 206 responds to the request by referencing the data structure 248 to determine whether the host computer 204 is authorized to have access to the first logical volume 244. In making this determination, the security module 218 may analyze authentication data included in the look-up request. For example, the security module 218 may compare a certificate received with the look-up request to those of an access control list maintained in the data structure 248. If the request is approved, the security module 218 extracts the appropriate path information regarding the first logical volume 244 from the data structure 248. The SAN domain controller 206 then sends the path information to the host computer 204 (Arrow G). The host computer 204 then uses the path information to access the first logical volume 244 via the storage area network 202 (Arrow H).
If the security module 218 determines that the host computer 204 is not permitted to have access to the first logical volume 244, then the SAN domain controller 206 sends a denial message to the host computer 204. There may be a variety of reasons for denying access to the host computer 204. For example it may be desirable to prevent the host computer 204 from corrupting the data in the first logical volume 244.
Referring again to
It can thus be seen that a new a useful method and system for managing stored data on a computer network has been provided. In view of the many possible embodiments to which the principles of this invention may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures is meant to be illustrative only and should not be taken as limiting the scope of invention. For example, those of skill in the art will recognize that the elements of the illustrated embodiments shown in software may be implemented in hardware and vice versa or that the illustrated embodiments can be modified in arrangement and detail without departing from the spirit of the invention. Therefore, the invention as described herein contemplates all such embodiments as may come within the scope of the following claims and equivalents thereof.