EP0709779A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Virtual shared disks with application-transparent recovery
Assignee: International Business Machines Corp
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Filing: 1995-10-06
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Granted: —
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Expires: 2015-10-06
Abstract
Abstract A system and method for recovering from failures in the disk access path of a clustered computing system. Each node of the clustered computing system is provided with proxy software for handling physical disk access requests from applications executing on the node and for directing the disk access requests to an appropriate server to which the disk is physically attached. The proxy software on each node maintains state information for all pending requests originating from that node. In response to detection of a failure along the disk access path, the proxy software on all of the nodes directs all further requests for disk access to a secondary node physically attached to the same disk.
Inventors
- 👤 Clement Richard Attanasio
- 👤 Maria Angela Butrico
- 👤 James Lyle Peterson
- 👤 Christos Alkiviadis Polyzois
- 👤 Stephen Edwin Smith
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 08:16
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/202; G06F11/2023; G06F11/2033; G06F15/00; G06F15/16; G06F11/14; G06F11/1402; G06F11/1415; G06F11/142; G06F11/1423; G06F11/1479; G06F11/2035; G06F11/2046; G06F11/2053; G06F11/2089; G06F11/2092; G06F2201/00; G06F2201/815
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
A method for recovering from failures in a disk access path of a clustered computing system, comprising the steps of: a) providing each given node of the clustered computing system with proxy logic for handling physical disk access requests from applications executing on the given node and for directing the disk access requests to a primary node to which the disk is physically attached; the proxy logic on each given node maintaining state information for all pending requests originating from that given node; b) detecting a failure along the access path to a disk; c) in response to detection of the failure, notifying the proxy software on all of the nodes to direct all further requests for access to the disk to a secondary node which is also physically attached to the the disk.
Claim 2
Dependent Claim
37 words
The method of Claim 1 wherein the access path includes the disk adapters and nodes to which the disk is physically attached and wherein the failure is detected in any of the nodes and the disk adapters.
Claim 3
Dependent Claim
44 words
The method of Claim 1 comprising the further steps of: in response to the detection of the failure, storing incomming access requests to the disk in a queue; and, rerouting the requests in the queue to the disk by way of the secondary node.
Claim 4
Dependent Claim
103 words
A clustered multi-processing system comprising a plurality of N nodes; a multiported disk having plurality of ports connected to M of the nodes, where N is greater than M; a failure detection mechanism, coupled to the nodes, for detecting failures along a disk access path between the disk and the nodes which are not physically connected to the disk; and, proxy logic on each of the nodes, coupled to the failure detection mechanism, for redirecting access requests to the multiported disk to another disk access path between the disk and the nodes not physically connected to the disk, when a failure is detected.
Claim 5
Dependent Claim
41 words
The system of Claim 4 comprising a queue, in each of the nodes, for storing incomming access requests to the disk; and, means for rerouting the requests in the queue to the disk by way of the another disk access path.
Claim 6
Dependent Claim
43 words
The system of Claim 4 wherein the failure detection mechanism includes means for detecting failures in any of the nodes physically attached to the disk and in disk adapters, coupled to the disk, in each of the nodes physically attached to the disk.
Claim 7
Independent Claim
147 words
A method for recovering from failures along a disk access path in a clustered computing system, comprising the steps of: detecting a failure in the disk access path in the clustered computing system; upon detection of the failure broadcasting a message to all nodes of the system having access to the disk; in response to the message, suspending virtual shared disks on each node, saving pending requests that had been sent to the disk along the failed access path and saving requests that arrive while a virtual shared disk is suspended; broadcasting a second message to the nodes to resume the affected virtual shared disks; upon receipt of the second message, resuming the virtual shared disks at each node by recording the node holding a new primary tail in a destination map for that virtual device; and, re-issuing all of the requests to the new primary tail.
References Cited (Backward Citations)
No citation records indexed.
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