Extended attribute caching in clustered filesystem

• US 20030028514A1
• Filed: 07/18/2002
• Published: 02/06/2003
• Est. Priority Date: 06/05/2001
• Status: Abandoned Application

• Current Assignee: Silicon Graphics International Corporation (Hewlett-Packard Enterprise Company)
• Original Assignee: Silicon Graphics International Corporation (Hewlett-Packard Enterprise Company)
• Inventors: Kierski, Robert, Lord, Stephen Philip
• Application Number:
  US10/197,211
• Publication Number:
  US 20030028514A1
• Time in Patent Office: Days
• US Class Current: 707/1
• CPC Class Codes: G06F 11/2064 while ensuring consistency
• CPC Class Codes: G06F 11/2082 Data synchronisation
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: H04L 67/10 in which an application is distributed across nodes in the network software deployment G06F8/60; multiprogramming arrangements G06F9/46
• CPC Class Codes: H04L 67/564 Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/566 Grouping or aggregating service requests, e.g. for unified processing
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A cluster of computer system nodes share direct read/write access to storage devices via a storage area network using a cluster filesystem. Version information about subsystems is acquired by a leader node when forming a cluster membership and distributed to all nodes in the cluster to enable proper messaging during operation. Access to files on the storage devices is arbitrated by the cluster filesystem using tokens. Upon detection of a change in location of the metadata server, client nodes waiting for a token are interrupted to check on the status of at least one of data and node availability. The cluster operating system maintains consistency of a mirrored data volume by automatically ensuring replication of a mirror leg while continuing to accept access requests to the mirrored data volume.

Claims

1. A method of operating a cluster of computer system nodes sharing direct read/write access to storage devices via a storage area network, comprising:

using tokens to control access by a client node to extended attributes for a filesystem administered by a metadata server node; and

caching the extended attributes at the client node when access to the extended attributes is permitted by the metadata server node.

2. A method as recited in claim 1, wherein the extended attributes include at least one access control list for the filesystem.

3. A method as recited in claim 1, wherein the extended attributes include at least one mandatory access control label for the filesystem.

4. At least one computer readable medium storing at least one program embodying a method of operating a cluster of computer system nodes sharing direct read/write access to storage devices via a storage area network, said method comprising:

using tokens to control access by a client node to extended attributes for a filesystem administered by a metadata server node; and

caching the extended attributes at the client node when access to the extended attributes is permitted by the metadata server node.

5. At least one computer readable medium as recited in claim 4, wherein the extended attributes include at least one access control list for the filesystem.

6. At least one computer readable medium as recited in claim 4, wherein the extended attributes include at least one mandatory access control label for the filesystem.

7. A cluster of computer systems, comprising:

storage devices storing at least one filesystem;

a storage area network coupled to said storage devices;

at least one metadata server node, coupled to said storage area network

metadata client nodes, coupled to said storage area network, using tokens to control access to extended attributes for a filesystem administered by said metadata server node and caching the extended attributes when access to the extended attributes is permitted by said metadata server node.

8. A cluster of computer systems as recited in claim 7, wherein the extended attributes include at least one access control list for the filesystem.

9. A cluster of computer systems as recited in claim 7, wherein the extended attributes include at least one mandatory access control label for the filesystem.