Modification of an object replica

• US 9,237,193 B2
• Filed: 04/09/2014
• Issued: 01/12/2016
• Est. Priority Date: 03/08/2011
• Status: Active Grant

• Current Assignee: Rackspace US Incorporated (Apollo Global Management, Inc.)
• Original Assignee: Rackspace US Incorporated (Apollo Global Management, Inc.)
• Inventors: Barton, Michael, Reese, Will, Dickinson, John A., Payne, Jay B., Thier, Charles B., Holt, Gregory
• Primary Examiner(s): Wong, Leslie
• Application Number:
  US14/249,306
• Publication Number:
  US 20140222949A1
• Time in Patent Office: 643 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/162 Delete operations erasing in storage systems G06F3/0652
• CPC Class Codes: G06F 16/1837 Management specially adapted to peer-to-peer storage networks topology management mechanisms of peer-to-peer networks H04L67/1042
• CPC Class Codes: G06F 16/219 Managing data history or versioning querying versioned data G06F16/2474; querying temporal data G06F16/2477
• CPC Class Codes: G06F 16/23 Updating
• CPC Class Codes: G06F 16/2322 using timestamps
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• 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]

Abstract

Several different embodiments of a massively scalable object storage system are described. The object storage system is particularly useful for storage in a cloud computing installation whereby shared servers provide resources, software, and data to computers and other devices on demand. In several embodiments, the object storage system includes a ring implementation used to associate object storage commands with particular physical servers such that certain guarantees of consistency, availability, and performance can be met. In other embodiments, the object storage system includes a synchronization protocol used to order operations across a distributed system. In a third set of embodiments, the object storage system includes a metadata management system. In a fourth set of embodiments, the object storage system uses a structured information synchronization system. Features from each set of embodiments can be used to improve the performance and scalability of a cloud computing object storage system.

Claims

1. A method for managing data items in a distributed storage pool, comprising:

providing a plurality of physical storage pools, each storage pool including a plurality of storage nodes coupled to a network, and each storage node further providing a non-transitory computer readable medium for data storage;

storing a first replica of a data item in a first physical storage pool of the plurality of physical storage pools;

receiving an instruction to delete the data item;

in response to receiving the instruction;

deleting the first replica of the data item from the first physical storage pool;

creating a first modification sentinel file based on the deleting; and

storing the first modification sentinel file in the first physical storage pool;

applying a hash function to a name of the first replica of the data item, wherein the first modification sentinel file includes a first output of the hash function;

encountering the first modification sentinel file during a data item replication process;

in response to encountering the first modification sentinel file, determining whether a configurable time has elapsed; and

in response to determining that the configurable time has not elapsed;

searching for replicas of the data item associated with the first modification sentinel file and stored in one or more of the plurality of physical storage pools; and

deleting the one or more replicas of the data item stored in the one or more of the plurality of physical storage pools.

2. The method of claim 1, further comprising:

storing a second replica of the data item in a second physical storage pool of the plurality of physical storage pools, wherein the searching includes identifying the second replica and the deleting includes deleting the second replica.

3. The method of claim 2, wherein the configurable time is longer than the worst-case replication propagation time between the first physical storage pool and the second physical storage pool.

4. The method of claim 1, wherein the modification sentinel file is a file deletion marker.

5. The method of claim 1, further comprising:

in response to determining that the configurable time has elapsed, deleting the first modification sentinel file.

6. The method of claim 5, further comprising:

applying a hash function to a name of the first replica of the data item, wherein the first modification sentinel file includes a first output of the hash function.

7. The method of claim 6, further comprising:

applying the hash function to a name of a replica of the data item.

8. The method of claim 1, wherein the first modification sentinel file is a 0 byte file.

9. The method of claim 7, wherein the replica of the data item is associated with the first modification sentinel file if an output of the applying includes the first output of the hash function.

10. A system for managing data items in a distributed storage pool, the system comprising:

a distributed storage system coupled to a network, the distributed storage system including a first storage pool and a second storage pool from a plurality of physical storage pools, the first and second storage pools each including at least one processor, a non-transitory computer readable medium, and a communications interface;

an object service that stores a first replica of a data item in the first storage pool and receives an instruction to delete the data item, wherein in response to receiving the instruction, the object service deletes the first replica of the data item from the first physical storage pool, creates a first modification sentinel file based on the deleting, stores the first modification sentinel file in the first physical storage pool, and applies a hash function to a name of the first replica of the data item, wherein the first modification sentinel file includes a first output of the hash function,

wherein the object service encounters the first modification sentinel file during a data item replication process and in response to encountering the first modification sentinel file, determines whether a configurable time has elapsed,

wherein in response to determining that the configurable time has not elapsed, the object services searches for replicas of the data item associated with the first modification sentinel file and stored in one or more of the plurality of physical storage pools and deletes the one or more replicas of the data item stored in the one or more of the plurality of physical storage pools.

11. The system of claim 10, further comprising:

a replicator that stores a second replica of the data item in the second storage pool of the plurality of physical storage pools, identifies the second replica, and deletes the second replica.

12. The system of claim 11, wherein the modification sentinel files are file deletion markers.

13. The system of claim 11, further comprising:

a timer triggering an action at the configurable time.

14. The system of claim 11, wherein in response to determining that the configurable time has elapsed, the replicator deletes the first modification sentinel file.

15. The system of claim 11, wherein if the configurable time has not elapsed, the replicator deletes the one or more replicas of the data item stored in the one or more of the plurality of physical storage pools.

16. The system of claim 13, wherein the configurable time is longer than the worst-case replication propagation time between the first storage pool and the second storage pool.

17. The system of claim 10, wherein the first modification sentinel file is a 0 byte file.