# US 9,438,675 B2 · Dispersed storage with variable slice length and methods for use therewith

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- Number: US 9,438,675 B2
- Document ID: US9438675B2
- Status: Granted
- Kind: B2
- Application number: 14/315,981
- Filed: 2014-06-26
- Published: 2015-03-05
- Granted: 2016-09-06
- Earliest claimed: 2013-08-29
- Assignees: International Business Machines Corporation
- Applicants: Cleversafe, Inc.
- Inventors: Andrew Baptist; Ilya Volvovski; Wesley Leggette; Greg Dhuse; Jason K. Resch
- Web page: https://patentgrep.com/patent/US9438675B2

## CPC

- 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]
- G06F 11/1096: {Parity calculation or recalculation after configuration or reconfiguration of the system}
- G06F 16/13: File access structures, e.g. distributed indices (arrangements of input from, or output to, record carriers G06F3/06)
- G06F 16/951: Indexing; Web crawling techniques
- G06F 16/953: Querying, e.g. by the use of web search engines
- G11C 29/44: Indication or identification of errors, e.g. for repair
- H04L 67/60: Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources (admission control or resource allocation H04L47/70)
- G06F 11/1076: {Parity data used in redundant arrays of independent storages, e.g. in RAID systems}
- G06F 2211/1028: Distributed, i.e. distributed RAID systems with parity
- G11C 2029/4402: {Internal storage of test result, quality data, chip identification, repair information}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A dispersed storage processing unit selects a slice length for a data segment to be stored in a dispersed storage network (DSN). The data segment is encoded using a dispersed storage error coding function to produce a set of data slices in accordance with the slice length. A storage file is selected based on the slice length. A storage file identifier (ID) is generated that indicates the storage file. A set of DSN addresses are generated corresponding to the set of data slices, wherein the set of DSN addresses each include the storage file ID and a corresponding one of a plurality of offset identifiers (IDs). The set of data slices are written in accordance with the set of DSN addresses. A directory is updated to associate the set of DSN addresses with an identifier of the data segment.

## Claims

### Claim 1

A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises:
selecting a first slice length for a first data segment of a data object to be stored in the DSN;
selecting a second slice length for a second data segment of the data object to be stored in the DSN;
encoding the first data segment using a first dispersed storage error coding function to produce a first set of data slices in accordance with the first slice length;
encoding the second data segment using a second dispersed storage error coding function to produce a second set of data slices in accordance with the second slice length;
selecting a first storage file based on the first slice length;
selecting a second storage file based on the second slice length;
generating a first storage file identifier (ID) that indicates the first storage file;
generating a second storage file identifier (ID) that indicates the second storage file;
generating a first set of DSN addresses corresponding to the first set of data slices and a second set of DSN addresses corresponding to the second set of data slices, wherein the first set of DSN addresses each include the first storage file ID and a corresponding one of a first plurality of offset identifiers (IDs) and the second set of DSN addresses each include the second storage file ID and a corresponding one of a second plurality of offset identifiers (IDs);
writing the first set of data slices in accordance with the first set of DSN addresses;
writing the second set of data slices in accordance with the second set of DSN addresses;
updating a directory to associate the first set of DSN addresses with an identifier of the first data segment; and
updating the directory to associate the second set of DSN addresses with an identifier of the second data segment.

### Claim 2 (depends on 1)

The method of claim 1 wherein the first storage file is selected when the first slice length has a first value and the second storage file is selected when the second slice length has a second value.

### Claim 3 (depends on 1)

The method of claim 1 wherein the first storage file is selected when the first slice length falls within a first range of values and the second storage file is selected when the second slice length falls within a second range of values.

### Claim 4 (depends on 1)

The method of claim 1 wherein the first storage file includes a first file header that includes the first plurality of offset identifiers and a first corresponding plurality of slice locations and the second storage file includes a second file header that includes the second plurality of offset identifiers and a second corresponding plurality of slice locations.

### Claim 5 (depends on 1)

The method of claim 1 wherein a data slice of the first set of data slices is stored in the first storage file with the first slice length at one of a first plurality of slice locations, and a data slice of the second set of data slices is stored in the second storage file with the second slice length at one of a second plurality of slice locations.

### Claim 6 (depends on 1)

The method of claim 1 wherein each of the first and second slice lengths is selected based on one or more of: a length of the first or second data segment, a predetermination, a vault identifier, a data type of the first or second data segment, or a storage utilization level.

### Claim 7 (depends on 1)

The method of claim 1 wherein the selecting of the first and second storage files is further based on one or more of: a data type of the first or second data segment, a data owner of the data segment, a vault identifier, a data priority level of the first or second data segment, or a preference of a DSN device.

### Claim 8

A dispersed storage processing unit of a dispersed storage network (DSN) comprises:
at least one module, when operable within a computing device, that causes the computing device to:
select a first slice length for a first data segment of a data object to be stored in the DSN;
select a second slice length for a second data segment of the data object to be stored in the DSN;
encode the first data segment using a first dispersed storage error coding function to produce a first set of data slices in accordance with the first slice length;
encode the second data segment using a second dispersed storage error coding function to produce a second set of data slices in accordance with the second slice length;
select a first storage file based on the first slice length;
select a second storage file based on the second slice length;
generate a first storage file identifier (ID) that indicates the first storage file;
generate a second storage file identifier (ID) that indicates the second storage file;
generate a first set of DSN addresses corresponding to the first set of data slices and a second set of DSN addresses corresponding to the second set of data slices, wherein the first set of DSN addresses each include the first storage file ID and a corresponding one of a first plurality of offset identifiers (IDs) and the second set of DSN addresses each include the second storage file ID and a corresponding one of a second plurality of offset identifiers (IDs);
write the first set of data slices in accordance with the first set of DSN addresses;
write the second set of data slices in accordance with the second set of DSN addresses;
update a directory to associate the first set of DSN addresses with an identifier of the first data segment; and
update the directory to associate the second set of DSN addresses with an identifier of the second data segment.

### Claim 9 (depends on 8)

The dispersed storage processing unit of claim 8 wherein the first storage file is selected when the first slice length has a first value and the second storage file is selected when the second slice length has a second value.

### Claim 10 (depends on 8)

The dispersed storage processing unit of claim 8 wherein the first storage file is selected when the first slice length falls within a first range of values and the second storage file is selected when the second slice length falls within a second range of values.

### Claim 11 (depends on 8)

The dispersed storage processing unit of claim 8 wherein the first storage file includes a first file header that includes the first plurality of offset identifiers and a first corresponding plurality of slice locations and the second storage file includes a second file header that includes the second plurality of offset identifiers and a second corresponding plurality of slice locations.

### Claim 12 (depends on 8)

The dispersed storage processing unit of claim 8 wherein a data slice of the first set of data slices is stored in the first storage file with the first slice length at one of a first plurality of slice locations, and a data slice of the second set of data slices is stored in the second storage file with the second slice length at one of a second plurality of slice locations.

### Claim 13 (depends on 8)

The dispersed storage processing unit of claim 8 wherein each of the first and second slice lengths is selected based on one or more of: a length of the first or second data segment, a predetermination, a vault identifier, a data type of the first or second data segment, or a storage utilization level.

### Claim 14 (depends on 8)

The dispersed storage processing unit of claim 8 wherein the selection of the first and second storage files is further based on one or more of: a data type of the first or second data segment, a data owner of the first or second data segment, a vault identifier, a data priority level of the data segment, or a preference of a DSN device.

### Claim 15

A non-transitory computer readable storage medium comprises:
at least one memory section that stores operational instructions that, when executed by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), causes the one or more computing devices to:
select a first slice length for a first data segment of a data object to be stored in the DSN;
select a second slice length for a second data segment of the data object to be stored in the DSN;
encode the first data segment using a first dispersed storage error coding function to produce a first set of data slices in accordance with the first slice length;
encode the second data segment using a second dispersed storage error coding function to produce a second set of data slices in accordance with the second slice length;
select a first storage file based on the first slice length;
select a second storage file based on the second slice length;
generate a first storage file identifier (ID) that indicates the first storage file;
generate a second storage file identifier (ID) that indicates the second storage file;
generate a first set of DSN addresses corresponding to the first set of data slices and a second set of DSN addresses corresponding to the second set of data slices, wherein the first set of DSN addresses each include the first storage file ID and a corresponding one of a first plurality of offset identifiers (IDs) and the second set of DSN addresses each include the second storage file ID and a corresponding one of a second plurality of offset identifiers (IDs);
write the first set of data slices in accordance with the first set of DSN addresses;
write the second set of data slices in accordance with the second set of DSN addresses;
update a directory to associate the first set of DSN addresses with an identifier of the first data segment; and
update the directory to associate the second set of DSN addresses with an identifier of the second data segment.

### Claim 16 (depends on 15)

The non-transitory computer readable storage medium of claim 15 wherein the first storage file is selected when the first slice length has a first value and the second storage file is selected when the second slice length has a second value.

### Claim 17 (depends on 15)

The non-transitory computer readable storage medium of claim 15 wherein the first storage file includes a first file header that includes the first plurality of offset identifiers and a first corresponding plurality of slice locations and the second storage file includes a second file header that includes the second plurality of offset identifiers and a second corresponding plurality of slice locations.

### Claim 18 (depends on 15)

The non-transitory computer readable storage medium of claim 15 wherein a data slice of the first set of data slices is stored in the first storage file with the first slice length at one of a first plurality of slice locations, and a data slice of the second set of data slices is stored in the second storage file with the second slice length at one of a second plurality of slice locations.

### Claim 19 (depends on 15)

The non-transitory computer readable storage medium of claim 15 wherein each of the first and second slice lengths is selected based on one or more of: a length of the first or second data segment, a predetermination, a vault identifier, a data type of the first or second data segment, or a storage utilization level.

### Claim 20 (depends on 15)

The non-transitory computer readable storage medium of claim 15 wherein the selection of the first and second storage files is further based on one or more of: a data type of the first or second data segment, a data owner of the first or second data segment, a vault identifier, a data priority level of the data segment, or a preference of a DSN device.