Electrical computers and digital processing systems: memory – Storage accessing and control – Control technique
Reexamination Certificate
2001-10-05
2004-02-24
Ellis, Kevin L. (Department: 2188)
Electrical computers and digital processing systems: memory
Storage accessing and control
Control technique
Reexamination Certificate
active
06697924
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention pertains to digital data processing and, more particularly, to storage area networks and methods of operation thereof. The invention has application, for example, in managing access by a plurality of digital data processors (e.g., web or file servers, graphical workstations and so forth) to a plurality of disk drives, disk arrays and other storage devices.
In early computer systems, long-term data storage was typically provided by dedicated storage devices, such as tape and disk drives, connected to a data central computer. Requests to read and write data generated by applications programs were processed by special-purpose input/output routines resident in the computer operating system. With the advent of “time sharing” and other early multiprocessing techniques, multiple users could simultaneously store and access data—albeit only through the central storage devices.
With the rise of the personal computer (and workstation) in the 1980's, demand by business users led to development of interconnection mechanisms that permitted otherwise independent computers to access data on one another's storage devices. Though computer networks had been known prior to this, they typically permitted only communications, not storage sharing.
The prevalent business network that has emerged is the local area network, typically comprising “client” computers (e.g., individual PCs or workstations) connected by a network to a “server” computer. Unlike the early computing systems in which all processing and storage occurred on a central computer, client computers usually have adequate processor and storage capacity to execute many user applications. However, they often rely on the server computer—and its associated battery of disk drives and storage devices—for other than short-term file storage and for access to shared application and data files.
An information explosion, partially wrought by the rise of the corporate computing and, partially, by the Internet, is spurring further change. Less common are individual servers that reside as independent hubs of storage activity. Often many storage devices are placed on a network or switching fabric that can be accessed by several servers (such as file servers and web servers) which, in turn, service respective groups of clients. Sometimes even individual PCs or workstations are enabled for direct access of the storage devices (though, in most corporate environments such is province of server-class computers) on these so-called “storage area networks.”
A drawback in prior art storage area networks arises in managing the proliferation of hosts and storage devices. Current solutions focus on setting switches or switch-like interfaces on the network or interconnect fabric between the hosts and storage device, electrically “blocking” certain hosts certain storage devices and so forth. A problem with these solutions is that they permit only zoning or switch-like control. Another problem is that, by their very nature, these solutions tend to be provider specific.
An object of this invention is to provide improved storage area networks and methods of operation thereof.
Further objects of the invention provide such methods and apparatus as facilitate access to multiple storage devices, e.g., of varied types, from a plurality of servers or other host digital data processors, e.g., running a variety of platforms.
Still further objects of the invention are to provide such methods and apparatus for managing administrator-defined and other policies for storage networks, e.g., to facilitate access by multiple hosts to multiple storage devices in a manner consistent with network administrators' wishes and without risk of unwanted access conflicts.
Yet still further objects of the invention are to provide such methods and apparatus as facilitate the persistence of status and other data pertaining to storage area networks regardless of the metaphors under which that data is used and/or stored (e.g., object-oriented, relational, and so forth).
Another object of the invention is to provide such methods and apparatus as facilitate automated handling of events that occur with respect to storage area networks and their componentry.
Yet other objects of the invention are to provide such methods and apparatus as facilitate visual representation of the storage area network topology, componentry and status.
Still yet another object of the invention is to provide such methods and apparatus as facilitate administrator (or other operator) definition of storage area network policy (e.g., vis-à-vis assignment of storage devices to hosts) and as facilitate notification of events occurring with respect thereto.
These and other objects of the invention are evident in the drawings and in the description that follow.
SUMMARY OF THE INVENTION
LUN Management
The foregoing are among the objects attained by the invention which provides, in one aspect, novel storage area networks (SANs) and methods of operation thereof. For example, in one aspect, the invention provides improvements on a SAN of the type having a plurality of hosts coupled via a network or other interconnect with one or more storage units. The improvement, according to this aspect of the invention, comprises a manager process, device or other functionality in communication with a plurality of agent processes, devices or other functionality, each of which is associated with a host. The agents identify attributes of (i) their associated hosts, (ii) the interconnect (or portion thereof) to which that host is coupled, and/or (iii) storage units to which that host is coupled via the interconnect. The manager responds to these attributes identified by the agents to manage the SAN.
The manager according to related aspects of the invention can be implemented on a first digital data processor, while the hosts are implemented on further digital data processors. These digital data processors can be coupled via a first network, e.g., an IP or other network, to support communications between the manager and the agents. Such communications can be further effected, according to one aspect of the invention, utilizing an object request broker (ORB). The interconnect, according to further related aspects of the invention, comprises a second network, e.g., SCSI and/or fiber channel based fabric, separate from the first network.
According to still further aspects of the invention, the manager provides one or more management functions including, by way of non-limiting example, interfacing with a SAN administrator, resolving SAN topology, managing storage device logical unit number assignment, and managing extension of host file systems. The agents can serve as proxies (or agents) for the manager, effecting functionality on its behalf at the host level. This functionality can include SAN component attribute collection, LUN masking control, host file system monitoring, and file system extension implementation.
Further aspects of the invention provide systems as describe above in which one or more agents utilize their associated hosts to query and otherwise gather information regarding storage devices to them (the hosts) via the interconnect. This information can include the number of logical units present on each physical storage device, the identification of the physical storage device and its respective logical units, and/or the storage capacity of each logical unit. Queries from the hosts to the devices can be effected via using the protocol of the interconnect, e.g., a SCSI protocol for a fiber channel interconnect.
In related aspects of the invention, the manager correlates information collected by the agents from their respective hosts, e.g., disambiguating identifies of logical units in the storage devices and, more typically, on the SAN, from potentially only partial (or incomplete) information supplied by each agent. In accord with policies established by the SAN administrator (and entered into the manager, e.g., via its graphical interface), the manager assigns logical units to the hos
Ellis Kevin L.
International Business Machines - Corporation
Nutter McClennen & Fish
Powsner David J.
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