Patent Application
20050198194
1. Field of the Invention
This invention relates in general to storage systems, and more particularly to a method, apparatus and program storage device for providing wireless storage.
2. Description of Related Art
As computer systems have evolved so has the availability and configuration of data storage devices, such as magnetic or optical disks. For example, these storage devices can be connected to the computer system via a bus, or they can be connected to the computer system via a wired or wireless network. In addition, the storage devices can be separate or co-located in a single cabinet.
As the amount of storage increases, and the number of file servers in communication networks grows, the concept of a storage area network (SAN) has arisen. Storage area networks connect a number of mass storage systems in a communication network, which is optimized for storage transactions. Thus, a storage network provides a collection of interconnected computing systems, referred to as nodes, operating as a single storage resource. A storage network allows a system to continue to operate during hardware or software failures, increases scalability by allowing nodes to be easily added and simplifies management by allowing an administrator to manage the nodes as a single system.
In a SAN, file servers and other users of the storage systems are configured to communicate with specific storage media via a network. For example, fiber channel arbitrated loop FC-AL networks are being implemented as SANs. The SANs support many point-to-point communication sessions between users of the storage systems and the specific storage systems on the SAN.
As with almost any network, there is always the need to reduce the complexity of wiring in today's constantly growing storage market, both from a load balancing and a connectivity point of view. Also, the desire to wire in new storage and storage appliances is gaining momentum. Coupled with these storage developments, there has been an increasing need for mobile computing in recent years. Mobile computing performs information processing by connecting to an existing Internet service network through a mobile-phone circuit, for example. As third-generation (3G) networks gain greater penetration, wireless connectivity will fuel growth in the burgeoning storage market by enabling new applications for database access and content sharing. Moreover, wireless storage technology could blossom on a more significant scale to change the way businesses share information and do business with customers.
Wireless applications for storage area networks include digital photography, location-based services, customer relationship management as well as unified messaging, voice information, and telematics. Wireless applications for storage area networks would also allow mission-critical customer service, business planning, and workflow automation applications to benefit from anytime, anywhere information collection and distribution. For example, improved products and more responsive customer service would be facilitated if field service, sales force and manufacturing personnel were connected in real-time to central repositories of information.
In addition, as the businesses and consumers increasingly go wireless, the concept of data storage on the go evolves to networks that let users store, retrieve and share just about anything from personal music collections to important client information and lifesaving data in emergencies. Online SAN technology could also transform the way entertainment is delivered.
These trends would represent an advance from what is already being seen in enterprise storage. For example, large corporations have deployed wired storage area networks (SANs) to provide access to a single database, often through web servers. The goal of a SAN is to integrate different types of storage subsystems such as high-throughput RAID, high-transaction rate RAID, near-line long-term archival storage, and short-term backup storage into a single system. Many firms also use network-attached storage (NAS), consisting of peripheral devices or systems dedicated to providing shared internal storage space. However, with wireless SANs, combined with an increasing array of mobile devices able to access them, the scope and possible uses of wireless storage networks could increase dramatically.
Finally, storage devices themselves are going beyond the traditional single and dual controller models to N-way controllers (i.e., N being 3 or more) managing a number of local and geographically distributed disk drives. This further complicates the writing busses, load balancing and the system robustness, all of which can be improved via a wireless approach.
It can be seen then that there is a need for a method, apparatus and program storage device for providing wireless storage.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method, apparatus and program storage device for providing wireless storage.
The present invention solves the above-described problems by providing a manageable wireless network that allows load balancing between nodes.
A system in accordance with the principles of the present invention includes a first wireless storage node, a network node and a plurality of wireless channels coupling the first wireless storage node and the network node, an assignment of the plurality of the wireless channels of the first wireless storage node being based upon loading.
In another embodiment of the present invention, a method for providing wireless storage is provided. The method includes assigning a first set of wireless channels to a first wireless storage node, assigning a second set of wireless channels to a wireless network node, monitoring a loading between the wireless network node and at least the first wireless storage node and modifying the assignment of wireless channels when the loading between the wireless network node and at least the first wireless storage node changes.
In another embodiment of the present invention, another wireless storage network is provided. This wireless storage network includes a plurality of wireless storage devices having at least one wireless interface each and a plurality of wireless channels, the wireless channels being assigned to the wireless interfaces of the plurality of wireless storage devices, wherein the load to the plurality of wireless storage devices is balanced by adjusting assignments of the plurality of wireless channels to the plurality of wireless storage devices.
In another embodiment of the present invention, a program storage device readable by a computer tangibly embodying one or more programs of instructions executable by the computer to perform a method for providing wireless storage is provided. The method includes assigning a first set of wireless channels to a first wireless storage node, assigning a second set of wireless channels to a wireless network node, monitoring a loading between the wireless network node and at least the first wireless storage node and modifying the assignment of wireless channels when the loading between the wireless network node and at least the first wireless storage node changes.
These and various other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto and form a part hereof. However, for a better understanding of the invention, its advantages, and the objects obtained by its use, reference should be made to the drawings which form a further part hereof, and to accompanying descriptive matter, in which there are illustrated and described specific examples of an apparatus in accordance with the invention.
Referring now to the drawings in which like reference numbers represent corresponding parts throughout:
In the following description of the embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration the specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized because structural changes may be made without departing from the scope of the present invention.
The present invention provides a method, apparatus and program storage device for providing wireless storage. The present invention provides a manageable wireless network for a storage area network that allows load balancing between nodes.
The concept of virtual memory has traditionally been used to enable physical memory to be virtualized through the translation between physical addresses in physical memory and virtual addresses in virtual memory. Recently, the concept of “virtualization” has been implemented in storage area networks through various mechanisms. Virtualization converts physical storage and virtual storage on a storage network. The hosts (initiators) see virtual disks as targets. The virtual disks represent available physical storage in a defined but somewhat flexible manner. Virtualization provides hosts with a representation of available physical storage that is not constrained by certain physical arrangements/allocation of the storage.
One early technique, Redundant Array of Independent Disks (RAID), provides some limited features of virtualization. Various RAID subtypes have been implemented. In RAID1, a virtual disk may correspond to two physical disks 116, 118 which both store the same data (or otherwise support recovery of the same data), thereby enabling redundancy to be supported within a storage area network. In RAID0, a single virtual disk is striped across multiple physical disks. Some other types of virtualization include concatenation, sparing, etc. Some aspects of virtualization have recently been achieved through implementing the virtualization function in various locations within the storage area network. Three such locations have gained some level of acceptance: virtualization in the hosts (e.g., 104-108), virtualization in the disk arrays or storage arrays (e.g., 110-114), and virtualization in a storage appliance 126 separate from the hosts and storage pool. Unfortunately, each of these implementation schemes has undesirable performance limitations.
Virtualization in the storage array is one of the most common storage virtualization solutions in use today. Through this approach, virtual volumes are created over the storage space of a specific storage subsystem (e.g., disk array). Creating virtual volumes at the storage subsystem level provides host independence, since virtualization of the storage pool is invisible to the hosts. In addition, virtualization at the storage system level enables optimization of memory access and therefore high performance. However, such a virtualization scheme typically will allow a uniform management structure only for a homogenous storage environment and even then only with limited flexibility. Further, since virtualization is performed at the storage subsystem level, the physical-virtual limitations set at the storage subsystem level are imposed on all hosts in the storage area network. Moreover, each storage subsystem (or disk array) is managed independently. Virtualization at the storage level therefore rarely allows a virtual volume to span over multiple storage subsystems (e.g., disk arrays), thus limiting the scalability of the storage-based approach.
Any of the wireless nodes 210-216 may be a wireless storage node for providing broad-spectrum wireless access to storage. In one embodiment, a plurality of the wireless nodes 210-216 are configured as wireless storage nodes that include a wireless adapter 220 with one or more transceivers 230. Depending upon the design, the wireless adapters 220 may be configured to provide a large number of frequencies for communication with other wireless storage nodes. Each frequency is capable of transmitting a given bandwidth, X MB/sec. Each wireless storage node 210-216 may be designed to have only the number of frequency channels needed for the bandwidth associated with that wireless storage node. For example, a wireless switch in a storage area network may need many more frequency channels than a storage array because the switch must communicate, for example, with the storage array and at least one host or server.
As load requirements change between different wireless storage nodes 210-216, the number of paths will change rapidly, e.g., hundreds of times a second, between each wireless storage node to properly balance the load. The only limitation to the speed is the amount of bandwidth that can be transmitted over the allowed frequency range. One of the wireless nodes 210-216 may control the assignment of the frequency channels.
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The foregoing description of the exemplary embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not with this detailed description, but rather by the claims appended hereto.
