Global file system-based system and method for rendering devices on a cluster globally visible

• US 6,047,332 A
• Filed: 06/30/1997
• Issued: 04/04/2000
• Est. Priority Date: 06/30/1997
• Status: Expired due to Term

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Sun Microsystems Incorporated (Oracle Corporation)
• Inventors: Khalidi, Yousef, Viswanathan, Srinivasan, Nazari, Siamak, Swaroop, Anil
• Primary Examiner(s): Asta, Frank J.
• Assistant Examiner(s): WILLETT, STEPHAN F
• Application Number:
  US08/885,149
• Time in Patent Office: 1,009 Days
• Field of Search: 709/201, 709/212, 709/213, 709/227, 709/243, 709/245, 709/214, 709/215, 709/216, 709/228, 709/229
• US Class Current: 709/245
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 9/5061 Partitioning or combining of resources

Abstract

A system and method are disclosed for rendering devices on a cluster globally visible, wherein the cluster includes a plurality of nodes on which the devices are attached. The system establishes for each of the devices in the cluster at least one globally unique identifier enabling global access to the device. The system includes a device registrar that creates the identifiers and a global file system. The identifiers include a globally unique logical name by which users of the cluster identify the device and a globally unique physical name by which the global file system identifies the device. The registrar creates a one-to-one mapping between the logical name and the physical name for each of the devices. The system also includes a device information (dev_-- info) data structure maintained by the device registrar that represents physical associations of the devices within the cluster. Each association corresponds to the physical name of a device file maintained by the global file system. The device registrar determines for an attached device a globally unique, device type (dev_-- t) value; creates dev_-- info data structure entry and a corresponding physical name; generates a logical name based on the dev_-- t value and the physical name; and associates the dev_-- t value with the device file representing the attached device. Given this framework, a user of the cluster can access any of the devices by issuing the global file system an access request identifying the device to be accessed by its logical name.

Claims

1. A system for rendering physical devices on a cluster globally visible, wherein the cluster includes a plurality of nodes on which the physical devices are attached, the system comprising:

a global file system running on the cluster;

a plurality of device drivers, each for managing a corresponding subset of the physical devices, each of the drivers being associated with a globally unique, major number; and

a device registrar configured to establish for each of the devices at least one globally unique identifier enabling that device to be accessed from any of the nodes, the globally unique identifier including;

a globally unique logical name by which users of the cluster identify the device; and

a globally unique physical name by which the global file system identifies the device, the globally unique physical name including a first portion corresponding to the device driver used to manage the device and a second portion corresponding to a minor name that is globally unique with respect to the device driver used to manage the device;

wherein there is a one-to-one mapping, established by the device registrar, between the logical name and the physical name for each of the devices.

2. The system of claim 1, further comprising:

a device information (dev_-- info) data structure maintained by the device registrar representing physical associations of the devices within the cluster, each of the physical associations corresponding to a physical name of a device file maintained by the global file system that represents a respective one of the devices;

wherein the device registrar is configured to;

determine for an attached device a globally unique, device type (dev_-- t) value;

create an entry in the dev_-- info data structure and a corresponding physical name for the attached device;

generate for the attached device a logical name based on the dev_-- t value and the corresponding physical name; and

associate the dev_-- t value of the attached device with the device file representing the attached device.

3. The system of claim 2, wherein the dev_-- info data structure comprises a dev_-- info tree representing physical associations of the devices within the cluster, each path between a root node and a leaf node of the tree corresponding to the globally unique physical name of the device file maintained by the global file system that represents a respective one of the devices.

4. The system of claim 2, wherein each of the nodes hosts at least a portion of the device registrar and the dev_-- info data structure.

5. The system of claim 1, wherein

each said device driver is configured to assign to each attached, local device it manages a local minor number;

the device registrar includes a device driver interface (DDI) configured to determine whether the local minor number assigned by any one of said device drivers to a particular one of the devices is globally unique, to convert the local minor number to a global minor number when the local minor number is not globally unique, and to generate the globally unique dev_-- t value for the particular device using the major number for the device driver corresponding to the particular device and the global minor number for the particular device.

6. The system of claim 2, wherein the device registrar comprises:

a device driver interface configured to map the globally unique dev_-- t values to the globally unique physical names; and

a link generator configured to map the globally unique physical names to the globally unique logical names.

7. The system of claim 6, wherein the devices are classified in predetermined device classes that include at least one of:

"dev_-- enumerate," for designating devices with at least one occurrence managed by a particular driver, each of the occurrence managed by the particular driver on a node being individually enumerated;

"dev_-- nodespecific," for designating devices available on each node that are accessed locally and have a one-to-one relationship with the managing driver on each node;

"dev_-- global," for designating devices for access from drivers on any such node; and

"dev_-- nodebound," for designating devices for access by a driver on a particular node and having a one-to-one relationship with the driver.

8. The system of claim 7, further comprising a device configuration system (DCS) hosted on one of the cluster nodes that maintains a persistent DCS database comprising for each device in the cluster a major number of the device driver that manages the device, the local minor number, the global minor number and an id of the node hosting the device;

wherein the DDI generates the globally unique identifier by request to the DCS and the DCS database.

9. The system of claim 8, wherein:

the DCS is configured to generate for each device of the dev_-- enumerate type a respective globally unique global minor number for substantially all device instances associated with the same driver; and

the DCS is configured to generate for each device of the dev_-- nodespecific type a first DCS database record wherein the dev_-- nodespecific type device is associated with a respective unique global minor number associated with no particular node, and a plurality of second DCS records corresponding in number to the number of the nodes, each second record associated with a respective, unique global minor number, such that the first record enables users to access the dev_-- nodespecific device locally and the second records enable user to access the dev_-- nodespecific device on any of the nodes.

10. The system of claim 9, further comprising:

one DSO for each of the device classes, each of the DSO'"'"'s storing information used to assign the global minor numbers to device instances of its respective device class;

the DCS being configured to utilize the DSO'"'"'s to assign the global minor numbers.

11. A computer program product, for use in each of at least a subset of a plurality of cluster nodes, at least a subset of which have associated physical devices, the computer program product comprising a computer readable storage medium and a computer program mechanism embedded therein, the computer program mechanism comprising:

a plurality of device drivers, each for managing a corresponding subset of the physical devices, each of the drivers being associated with a globally unique, major number; and

a device registrar configured to establish for each of the devices at least one globally unique identifier enabling that device to be accessed from any of the nodes, the globally unique identifier including;

a globally unique logical name by which users of the cluster identify the device; and

a globally unique physical name by which a global file system, associated with a system containing the plurality of cluster nodes, identifies the device, the globally unique physical name including a first portion corresponding to the device driver used to manage the device and a second portion corresponding to a minor name that is globally unique with respect to the device driver used to manage the device;

wherein there is a one-to-one mapping, established by the device registrar, between the logical name and the physical name for each of the devices.

12. The computer program product of claim 11, further comprising:

a device information (dev_-- info) data structure maintained by the device registrar representing physical associations of the devices within the cluster, each of the physical associations corresponding to a physical name of a device file maintained by the global file system that represents a respective one of the devices;

wherein the device registrar is configured to;

determine for an attached device a globally unique, device type (dev_-- t) value;

create an entry in the dev_-- info data structure and a corresponding physical name for the attached device;

generate for the attached device a logical name based on the dev_-- t value and the corresponding physical name; and

associate the dev_-- t value of the attached device with the device file representing the attached device.

13. The computer program product of claim 12, wherein the dev_-- info data structure comprises a dev_-- info tree representing physical associations of the devices within the cluster, each path between a root node and a leaf node of the tree corresponding to the globally unique physical name of the device file maintained by the global file system that represents a respective one of the devices.

14. The computer program product of claim 12, wherein each of the nodes hosts at least a portion of the device registrar and the dev_-- info data structure.

15. The computer program product of claim 12, wherein

each said device driver is configured to assign to each attached, local device it manages a local minor number;

the device registrar includes a device driver interface (DDI) configured to determine whether the local minor number assigned by any one of said device drivers to a particular one of the devices is globally unique, to convert the local minor number to a global minor number when the local minor number is not globally unique, and to generate the globally unique dev_-- t value for the particular device using the major number for the device driver corresponding to the particular device and the global minor number for the particular device.

16. The computer program product of claim 12, wherein the device registrar comprises:

a device driver interface configured to map the globally unique dev_-- t values to the globally unique physical names; and

a link generator configured to map the globally unique physical names to the globally unique logical names.

17. The system of claim 16, wherein the devices are classified in predetermined device classes that include at least one of:

"dev_-- enumerate," for designating devices with at least one occurrence managed by a particular driver, each of the occurrence managed by the particular driver on a node being individually enumerated;

"dev_-- nodespecific," for designating devices available on each node that are accessed locally and have a one-to-one relationship with the managing driver on each node;

"dev_-- gobal," for designating devices for access from drivers on any such node; and

"dev_-- nodebound," for designating devices for access by a driver on a particular node and having a one-to-one relationship with the driver.

18. The system of claim 17, further comprising a device configuration system (DCS) hosted on one of the cluster nodes that maintains a persistent DCS database comprising for each device in the cluster a major number of the device driver that manages the device, the local minor number, the global minor number and an id of the node hosting the device;

wherein the DDI generates the globally unique identifier by request to the DCS and the DCS database.

19. The system of claim 18, wherein:

the DCS is configured to generate for each device of the dev_-- enumerate type a respective globally unique global minor number for substantially all device instances associated with the same driver; and

the DCS is configured to generate for each device of the dev_-- nodespecific type a first DCS database record wherein the dev_-- nodespecific type device is associated with a respective unique global minor number associated with no particular node, and a plurality of second DCS records corresponding in number to the number of the nodes, each second record associated with a respective, unique global minor number, such that the first record enables users to access the dev_-- nodespecific device locally and the second records enable user to access the dev_-- nodespecific device on any of the nodes.

20. A method of enabling global access to physical devices located at a subset of a plurality of cluster nodes, comprising:

providing a plurality of device drivers, each for managing a corresponding subset of the physical devices, and associating with each of the drivers a globally unique, major number;

establishing for each of the devices at least one globally unique identifier enabling that device to be accessed from any of the nodes, the globally unique identifier including;

a globally unique logical name by which users of the cluster identify the device; and

a globally unique physical name by which a global file system, associated with a system containing the plurality of cluster nodes, identifies the device, the globally unique physical name including a first portion corresponding to the device driver used to manage the device and a second portion corresponding to a minor name that is globally unique with respect to the device driver used to manage the device;

wherein there is a one-to-one mapping, between the globally unique logical name and the globally unique physical name for each of the devices.

21. The method of claim 20, further comprising:

storing a device information (dev_-- info) data structure representing physical associations of the devices within the cluster, each of the physical associations corresponding to a physical name of a device file maintained by the global file system that represents a respective one of the devices;

determining for an attached device a globally unique, device type (dev_-- t) value;

creating an entry in the dev_-- info data structure and a corresponding physical name for the attached device;

generating for the attached device a logical name based on the dev_-- t value and the corresponding physical name; and

associating the dev_-- t value of the attached device with the device file representing the attached device.

22. The method of claim 21, wherein the step of storing the dev_-- info data structure including storing a dev_-- info tree representing physical associations of the devices within the cluster, each path between a root node and a leaf node of the tree corresponding to the globally unique physical name of the device file maintained by the global file system that represents a respective one of the devices.

23. The method of claim 21, wherein each of the nodes in the subset of nodes hosts at least a portion of the dev_-- info data structure.

24. The method of claim 21, wherein

using said device drivers, assigning to each device a local minor number;

determining whether the local minor number assigned by any one of said device drivers to a particular one of the devices is globally unique, converting the local minor number to a global minor number when the local minor number is not globally unique, and generating the globally unique dev_-- t value for the particular device using the major number for the device driver corresponding to the particular device and the global minor number for the particular device.

25. The method of claim 21, including:

mapping the globally unique dev_-- t values to the globally unique physical names; and

mapping the globally unique physical names to the globally unique logical names.

26. The method of claim 25, including classifying the devices in predetermined device classes that include at least one of:

"dev_-- enumerate," for designating devices with at least one occurrence managed by a particular driver, each of the occurrence managed by the particular driver on a node being individually enumerated;

"dev_-- nodespecific," for designating devices available on each node that are accessed locally and have a one-to-one relationship with the managing driver on each node;

"dev_-- gobal," for designating devices for access from drivers on any such node; and

"dev_-- nodebound," for designating devices for access by a driver on a particular node and having a one-to-one relationship with the driver.

27. The method of claim 26, including maintaining a persistent DCS database that stores for each device in the cluster a major number of the device driver that manages the device, the local minor number, the global minor number and an id of the node hosting the device.