Adaptive namespace verification for cluster filesystems

Patent metadata

Field	Value
Publication number	US-12061575-B2
Application number	US-202217958792-A
Country	US
Kind code	B2
Filing date	Oct 3, 2022
Priority date	Oct 3, 2022
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

Embodiments for providing adaptive namespace verification with high efficiency. The verification process is used in modern filesystems to check the integrity of key data structures, such for backup systems where providing thorough and efficient mechanisms for verification is critical. Embodiments accelerate the verification process by selectively applying continuous, differential, and integral verification techniques for startup and runtime repair purposes to overcome present problems for system capacities that exceed the petabyte range and impose significant time requirements using existing verification methods. Embodiments work with both single-node and distributed filesystems.

First claim

What is claimed is:

1. A method of verifying filesystem data in a cluster filesystem using an adaptive verification process, comprising:
maintaining metadata and file data wherein the metadata is processed using front-end nodes, and the file data is processed using back-end nodes;
tracking cluster events on a directory tree basis for each node of the cluster filesystem;
obtaining state information of the cluster filesystem about the front and back-end nodes;
obtaining load balancer information about load balancer to node assignments, wherein the load balancer selects which node should field specific client data traffic; and
dynamically determining an adaptive verification process selected from at least one of continuous verification, differential verification, and integral verification based on the tracked cluster events, the state information, and the load balancer information.

2. The method of claim 1 further comprising periodically executing a snapshot process that provides a consistent point-in-time image between the metadata and corresponding file data.

3. The method of claim 2 wherein the continuous verification comprises a verification process run independently on each node and utilizes namespace operations including file creates, updates, and deletes logged into a transaction log to continuously verify the filesystem data using a verification thread operating on a verification cache.

4. The method of claim 3 wherein the differential verification comprises a periodic process distributed among the nodes and comprises comparing snapshot copies of a current state and a previous verified state of the filesystem using the node assignments.

5. The method of claim 4 wherein the integral verification comprises taking an entire sweep of filesystem metadata by comparing periodic snapshots of the filesystem on a node-by-node basis.

6. The method of claim 1 wherein the cluster events comprise at least one of:
a node restart for one or more nodes of the cluster, a garbage collection completion, and normal operation.

7. The method of claim 6 wherein continuous verification is used for the node restart cluster event, integral verification is used for a cluster event of the garbage collection completion, and differential verification is used for a cluster event of the normal operation.

8. The method of claim 7 further comprising tracking additional events in an adaptive namespace verification module (AVM), wherein the additional events comprise system crashes, inbound load conditions seen by the load balancer, and long-term aging of data.

9. The method of claim 8 further comprising implementing an AVM policy in response to one or more of the additional events, and wherein the AVM policies comprise adjusting verification process operational characteristics for the continuous verification, differential verification, and integral verification.

10. The method of claim 1 wherein the cluster filesystem comprises a network of individual nodes having a log-structured file system implemented in a Data Domain Filesystem, and wherein the namespace contains file metadata implemented as a B+ tree comprising a balanced tree of fixed depth, wherein a node is a page of space, and related metadata is stored in leaf pages.

11. A method of verifying filesystem data in a cluster filesystem using an adaptive verification process, comprising:
defining a rules driven knowledge base to implement a verification strategy based on defined cluster events and dynamic events;
periodically executing a snapshot process that provides a consistent point-in-time image between metadata and corresponding filesystem data; and
implementing at least one of continuous verification, differential verification, and integral verification based on the defined cluster events and system events, wherein the continuous verification comprises a verification process that utilizes namespace operations including file creates, updates, and deletes logged into a transaction log to continuously verify the filesystem data using a verification thread operating on a verification cache, the differential verification comprises a periodic process comparing snapshot copies of a current state and a previous verified state of cluster filesystem, and the integral verification comprises taking an entire sweep of filesystem metadata by comparing periodic snapshots of the filesystem on a node-by-node basis.

12. The method of claim 11 wherein the defined cluster events comprise at least one of: a node restart, a garbage collection completion, and normal operation, and wherein continuous verification is used for a cluster event of the node restart, integral verification is used for a cluster event of the garbage collection completion, and differential verification is used for a cluster event of the normal operation.

13. The method of claim 12 wherein the dynamic events comprise system crashes, inbound load conditions seen by a load balancer, and long-term aging of data.

14. The method of claim 13 further comprising implementing a policy in response to one or more of the dynamic events, and wherein policies comprise adjusting verification process operational characteristics for the continuous verification, differential verification, and integral verification.

15. The method of claim 11 wherein the cluster filesystem comprises a network of individual nodes having a log-structured file system implemented in a Data Domain Filesystem, wherein the namespace contains file metadata implemented as a B+ tree comprising a balanced tree of fixed depth, wherein a node is a page of space, and related metadata is stored in leaf pages, wherein the cluster filesystem separately maintains the metadata and file data, and wherein the metadata is processed using front-end nodes, and the file data is processed using back-end nodes.

16. A method of verifying filesystem data in a cluster filesystem using an adaptive verification process, comprising:
defining a rules driven knowledge base to implement a verification strategy based on defined cluster events and dynamic events;
periodically executing a snapshot process that provides a consistent point-in-time image between metadata and corresponding filesystem data; and
implementing at least one of continuous verification, differential verification, and integral verification based on the defined cluster events and system events, wherein the defined cluster events comprise at least one of: a node restart, a garbage collection completion, and normal operation, and wherein the dynamic events comprise system crashes, inbound load conditions seen by a load balancer, and long-term aging of data.

17. The method of claim 16 wherein continuous verification is used for a cluster event of the node restart, integral verification is used for a cluster event of the garbage collection completion, and differential verification is used for a cluster event of the normal operation.

18. The method of claim 17 further comprising implementing a policy in response to one or more of the dynamic events, and wherein policies comprise adjusting verification process operational characteristics for the continuous verification, differential verification, and integral verification.

19. The method of claim 18 wherein: the continuous verification comprises a verification process utilizes namespace operations including file creates, updates, and deletes logged into a transaction log to continuously verify the filesystem data using a verification thread operating on a verification cache, the differential verifica

Assignees

• Dell Products Lp

Inventors

• Hickey Charles J
• Lakshmikantha Shashikanth
• Mamidi Murthy V

Classifications

• G06F16/128 Primary

  Details of file system snapshots on the file-level, e.g. snapshot creation, administration, deletion (error detection or correction of the data by redundancy in operations or in hardware G06F11/14, G06F11/16) · CPC title

• G06F16/1734 Primary

  Details of monitoring file system events, e.g. by the use of hooks, filter drivers, logs · CPC title