Clustered filesystem with data volume snapshot

• US 9,020,897 B2
• Filed: 08/28/2013
• Issued: 04/28/2015
• Est. Priority Date: 06/05/2001
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Silicon Graphics International Corporation (Hewlett-Packard Enterprise Company)
• Inventors: Beck, Kenneth
• Primary Examiner(s): Beausoliel, Jr., Robert
• Assistant Examiner(s): ALLEN, NICHOLAS E
• Application Number:
  US14/012,894
• Publication Number:
  US 20130346371A1
• Time in Patent Office: 608 Days
• Field of Search: None
• US Class Current: 707/640
• 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: G06F 16/128 Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion use of snapshots for error detection or correction G06F11/14, G06F11/16
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• 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 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• 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
• CPC Class Codes: Y10S 707/966 Distributed

Abstract

A computer system with read/write access to storage devices creates a snapshot of a data volume at a point in time while continuing to accept access requests to the mirrored data volume by copying before making changes to the base data volume. Multiple snapshots may be made of the same data volume at different points in time. Only data that is not stored in a previous snapshot volume or in the base data volume are stored in the most recent snapshot volume.

Claims

1. A method for recovering a viable quorum cluster of computers, the method comprising:

detecting a failed node in an initial viable quorum cluster by at least one node in the viable cluster when a member of the viable quorum cluster fails;

disabling message channels by the at least one node between the at least one node and the failed node after detecting the failed node;

disconnecting membership in the viable quorum cluster by the at least one node after disabling message channels after detecting the failed node;

blocking new nodes from joining the membership of the viable quorum cluster after detecting the failed node;

sending a withdrawal request from one node in the viable cluster to other nodes in the viable cluster when one node intends to deactivate from the viable quorum cluster in an orderly fashion;

electing a recovery leader;

initializing the recovery process;

initiating message interrupts;

initiating create locks;

preventing new accesses to objects associated with the recovery;

returning client tokens held;

purging states associated with a client;

thawing the message channels; and

releasing the create locks.

2. The method of claim 1, further comprising:

establishing a new membership of the viable quorum cluster;

sending an acknowledgement to the node that requested withdrawal from membership; and

transitioning the node that requested withdrawal from membership to a shutdown state.

3. The method of claim 2, further comprising upgrading software on the node previously in the shutdown state.

4. The method of claim 3, further comprising:

entering the nascent state by the node previously in the shutdown state;

sending heartbeat signals from the node in the nascent state; and

the node in the nascent state joining the viable quorum cluster.

5. The method of claim 1, further comprising:

flushing credentials of the failed node;

acknowledging that the credentials of the failed node have been flushed;

recovering the kernel object relocation engine;

recovering the volume manager;

recovering the filesystem; and

allowing new nodes to join the viable quorum cluster.

6. The method of claim 1 further comprising:

voting to elect a server host by remaining nodes;

selecting by the filesystem a next surviving node a possible server for the file system;

creating a manifest for each server on the failed node;

sending the manifest to the elected server host;

extracting information from the manifest;

sending a ready to commit instantiate callout message to the recovery leader; and

saving information relating to the extent of recovery.

7. The method of claim 6, further comprising:

recovering the kernel object relocation engine in a first recovery pass;

recovering the volume manager in a second recovery pass; and

recovering the filesystem in a third recovery pass.