Efficient data reads from distributed storage systems

Patent metadata

Field	Value
Publication number	US-9323615-B2
Application number	US-201414169322-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Jan 31, 2014
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A method of distributing data in a distributed storage system includes receiving a file into non-transitory memory and dividing the received file into chunks. The chunks are data-chunks and non-data chunks. The method also includes grouping one or more of the data chunks and one or more of the non-data chunks in a group. One or more chunks of the group is capable of being reconstructed from other chunks of the group. The method also includes distributing the chunks of the group to storage devices of the distributed storage system based on a hierarchy of the distributed storage system. The hierarchy includes maintenance domains having active and inactive states, each storage device associated with a maintenance domain, the chunks of a group are distributed across multiple maintenance domains to maintain the ability to reconstruct chunks of the group when a maintenance domain is in an inactive state.

First claim

What is claimed is:

1. A method of distributing data in a distributed storage system, the method comprising:
receiving a file into non-transitory memory;
dividing the received file into chunks using a computer processor in communication with the non-transitory memory, the chunks being data-chunks and non-data chunks;
grouping one or more of the data chunks and one or more of the non-data chunks in a group, one or more of the data chunks or one or more of the non-data chunks of the group capable of being reconstructed from other chunks of the group; and
determining a distribution of the chunks of the group among storage devices of the distributed storage system based on a maintenance hierarchy of the distributed storage system, the maintenance hierarchy comprising maintenance domains having active and inactive states, each storage device associated with a maintenance domain, wherein the distribution comprises a random selection of storage devices matching a number of the chunks of the group capable of maintaining accessibility of the group when one or more maintenance domains are in the inactive state; and
distributing the chunks of the group to the storage devices based on the determined distribution, the chunks of the group being distributed across multiple maintenance domains to maintain an ability to reconstruct chunks of the group when a maintenance domain is in the inactive state.

2. The method of claim 1 , further comprising restricting a number of chunks of the group distributed to the storage devices of any one maintenance domain.

3. The method of claim 1 , wherein when the random selection of the storage devices is incapable of maintaining accessibility of the group when one or more maintenance domains are in the inactive state, modifying the random selection of the storage devices by adding and/or removing one or more randomly selected storage devices.

4. The method of claim 1 , further comprising determining the random selection of the storage devices using a simple sampling, a probability sampling, a stratified sampling, or a cluster sampling.

5. The method of claim 1 , further comprising:
determining, using the computer processor, the maintenance hierarchy of maintenance domains, the maintenance hierarchy having maintenance levels, each maintenance level comprising one or more maintenance domains; and
mapping each maintenance domain to at least one storage device.

6. The method of claim 5 , wherein each maintenance domain comprises storage devices powered by a single power distribution unit or a single power bus duct.

7. A method of distributing data in a distributed storage system, the method comprising:
receiving a file into non-transitory memory;
dividing the received file into chunks using a computer processor in communication with the non-transitory memory, the chunks being data-chunks and non-data chunks;
grouping one or more of the data chunks and one or more of the non-data chunks in a group, one or more of the data chunks or one or more of the non-data chunks of the group capable of being reconstructed from other chunks of the group;
determining a distribution of the chunks of the group among storage devices of the distributed storage system based on a maintenance hierarchy of the distributed storage system by selecting a consecutive number of the storage devices equal to a number of the chunks of the group from an ordered circular list of the storage devices of the distributed storage system, the maintenance hierarchy comprising maintenance domains having active and inactive states, each storage device associated with a maintenance domain, the chunks of the group distributed across multiple maintenance domains to maintain an ability to reconstruct chunks of the group when a maintenance domain is in the inactive state, and when the selected storage devices are collectively incapable of maintaining the ability to reconstruct chunks of the group when a maintenance domain is in the inactive state, selecting another consecutive number of storage devices from the ordered circular list equal to the number of chunks of the group; and
distributing the chunks of the group to the storage devices of the distributed storage system based on the determined distribution.

8. The method of claim 7 , further comprising determining the ordered circular list of storage devices of the distributed storage system, adjacent storage devices on the ordered circular list associated with different maintenance domains.

9. The method of claim 8 , wherein a threshold number of consecutive storage devices on the ordered circular list are each associated with different maintenance domains.

10. The method of claim 8 , wherein a threshold number of consecutive storage devices on the ordered circular list are each in different geographical locations.

11. A method of distributing data in a distributed storage system, the method comprising:
receiving a file into non-transitory memory;
dividing the received file into stripes and each stripe into chunks using a computer processor in communication with the non-transitory memory, the chunks being data-chunks and non-data chunks, each file including an error correcting code, the error correcting code comprising one of a nested code or a layered code, the non-data chunks comprising code-check chunks, word-check chunks, and code-check-word-check chunks;
grouping one or more of the data chunks and one or more of the non-data chunks in a group, one or more of the data chunks or one or more of the non-data chunks of the group capable of being reconstructed from other chunks of the group; and
distributing the chunks of the group to storage devices of the distributed storage system based on a maintenance hierarchy of the distributed storage system, the maintenance hierarchy comprising maintenance domains having active and inactive states, each storage device associated with a maintenance domain, the chunks of the group being distributed across multiple maintenance domains to maintain an ability to reconstruct chunks of the group when a maintenance domain is in the inactive state.

12. A system for distributing data in a distributed storage system, the system comprising:
non-transitory memory receiving a file;
a computer processor in communication with the non-transitory memory, the computer processor:
dividing the received file into chunks, the chunks being data-chunks and non-data chunks; and
grouping one or more of the data chunks and one or more of the non-data chunks in a group, one or more of the data chunks or one or more of the non-data chunks of the group capable of being reconstructed from other chunks of the group; and

storage devices in communication with the computer processor and the non-transitory memory, the computer processor:
determining a distribution of the chunks of the group among the storage devices based on a maintenance hierarchy of the distributed storage system, the maintenance hierarchy comprising maintenance domains having active and inactive states, each storage device associated with a maintenance domain, wherein the distribution comprises a random selection of the storage devices matching a number of the chunks of the group capable of maintaining accessibility of the group when one or more maintenance domains are in the inactive state; and
distributing the chunks of the group to the storage devices based on the determined distribution, the chunks of the group distributed across multiple maintenance domains to maintain accessibility of the group when a maintenance domain is in the inactive state.

13. The system of claim 12 , wherein the computer processor restricts a number of the chunks

Assignees

• Google Inc

Inventors

• Cypher Robert
• Quinlan Sean
• Schirripa Steven Robert
• Carmi Lidor
• Schrock Christian Eric

Classifications

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title

• G06F11/0793

  Remedial or corrective actions (recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40) · CPC title

• G06F11/1076 Primary

  Parity data used in redundant arrays of independent storages, e.g. in RAID systems · CPC title

• G06F3/0643

  Management of files · CPC title

• G06F2211/1028

  Distributed, i.e. distributed RAID systems with parity · CPC title