# US 2017/0286154 A1 · Cycling out dispersed storage processing units from access pools to perform expensive operations

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- Number: US 2017/0286154 A1
- Document ID: US20170286154A1
- Status: Published application
- Kind: A1
- Application number: 15/467,121
- Filed: 2017-03-23
- Published: 2017-10-05
- Earliest claimed: 2016-03-29
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Andrew D. Baptist; Ravi V. Khadiwala
- Web page: https://patentgrep.com/patent/US20170286154A1

## CPC

- G06F 3/0619: {in relation to data integrity, e.g. data losses, bit errors}
- G06F 3/0604: {Improving or facilitating administration, e.g. storage management}
- G06F 3/061: {Improving I/O performance}
- G06F 3/0611: {in relation to response time}
- G06F 3/0631: {by allocating resources to storage systems}
- G06F 3/0635: {by changing the path, e.g. traffic rerouting, path reconfiguration}
- G06F 3/064: {Management of blocks}
- G06F 3/0644: {Management of space entities, e.g. partitions, extents, pools}
- G06F 3/0647: {Migration mechanisms}
- G06F 3/0659: {Command handling arrangements, e.g. command buffers, queues, command scheduling}
- G06F 3/067: {Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]}
- G06F 8/65: Updates (security arrangements therefor G06F21/57)
- G06F 9/485: {Task life-cycle, e.g. stopping, restarting, resuming execution (G06F9/4881 takes precedence)}
- G06F 9/4881: {Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues}
- G06F 11/1076: {Parity data used in redundant arrays of independent storages, e.g. in RAID systems}
- G06F 11/1092: {Rebuilding, e.g. when physically replacing a failing disk}
- G06F 21/31: User authentication
- H03M 13/05: using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits {(H03M13/2906 takes precedence)}
- H04L 61/10: of different types
- H04L 61/50: Address allocation
- H04L 63/08: {for authentication of entities (cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32)}
- H04L 63/104: {Grouping of entities}
- H04L 63/108: {when the policy decisions are valid for a limited amount of time}
- 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]
- H04L 67/56: Provisioning of proxy services (store-and-forward switching systems in data switching networks H04L12/54)
- G06F 2221/2133: Verifying human interaction, e.g., Captcha
- H03M 13/1515: {Reed-Solomon codes}
- H03M 13/373: {with erasure correction and erasure determination, e.g. for packet loss recovery or setting of erasures for the decoding of Reed-Solomon codes}
- H03M 13/616: {Matrix operations, especially for generator matrices or check matrices, e.g. column or row permutations}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

A method includes identifying, by a dispersed storage (DS) processing unit of a plurality of DS processing units of a dispersed storage network (DSN), a DSN operation to be performed that will adversely interfere with processing of DSN access requests. The method further includes sending, by the DS processing unit, a suspension request to a process balancing module of the DSN where the suspension request is for temporarily suspending processing of DSN access requests. The method further includes determining, by the process balancing module, whether sufficient processing resources of active DS processing units of the plurality of DS processing units are available for processing DSN access requests on behalf of the DS processing unit. When determined that sufficient processing resources are available, the method further includes granting the suspension request, and allocating DSN access requests of the DS processing unit to one ore of the active DS processing units.

## Claims

### Claim 1

A method comprises:
identifying, by a dispersed storage (DS) processing unit of a plurality of DS processing units of a dispersed storage network (DSN), a DSN operation to be performed that will adversely interfere with processing of DSN access requests;
sending, by the DS processing unit, a suspension request to a process balancing module of the DSN, wherein the suspension request is for temporarily suspending processing of DSN access requests;
determining, by the process balancing module, whether sufficient processing resources of active DS processing units of the plurality of DS processing units are available for processing DSN access requests on behalf of the DS processing unit; and
when determined that sufficient processing resources are available:
granting, by the process balancing module, the suspension request; and
allocating, by the process balancing module, DSN access requests of the DS processing unit to one or more of the active DS processing units.

### Claim 2 (depends on 1)

The method of claim 1 further comprises:
executing, by the DS processing unit, the DSN operation;
upon completion of execution of the DSN operation, sending, by the DS processing unit, a return notification to the process balancing module; and
in response to the return notification, resuming, by the process balancing module, allocation of the DSN access requests of the DS processing unit to the DS processing unit.

### Claim 3 (depends on 1)

The method of claim 1 further comprises:
the DSN operation including one or more of garbage collection, software update, a system administration operation, and a diagnostic operation; and
the DSN access requests including two or more of a read request, a write request, a rebuild request, a list request, a delete request, and a modify request.

### Claim 4 (depends on 1)

The method of claim 1 further comprises:
when determined that sufficient processing resources are not available, temporarily denying, by the process balancing module, the suspension request until sufficient processing resources become available.

### Claim 5 (depends on 1)

The method of claim 1, wherein the determining that sufficient processing resources are available comprises:
determining, by the process balancing module, a duration for which the DS processing unit will be unavailable for processing the DSN access requests of the DS processing unit;
estimating, by the process balancing module, processing requirements for processing the DSN access requests of the DS processing unit;
determining, by the process balancing module, a number of other DS processing units of the plurality of DS processing units that are currently in a temporary suspension mode;
estimating, by the process balancing module, processing requirements for processing other DSN access requests by the active DS processing units during the duration; and
determining, by the process balancing module, processing capabilities of the active DS processing units.

### Claim 6 (depends on 1)

The method of claim 1, wherein the allocating the DSN access requests of the DS processing unit further comprises:
allocating, by the process balancing module, the DSN access requests of the DS processing unit to the active DS processing units in accordance with a load balancing function.

### Claim 7 (depends on 1)

The method of claim 1, wherein the allocating the DSN access requests of the DS processing unit further comprises:
allocating, by the process balancing module, read requests to a first active DS processing unit of the one or more active DS processing units;
allocating, by the process balancing module, write requests to a second active DS processing unit of the one or more active DS processing units;
allocating, by the process balancing module, list requests to a third active DS processing unit of the one or more active DS processing units; and
allocating, by the process balancing module, rebuild support requests to a fourth active DS processing unit of the one or more active DS processing units.

### Claim 8 (depends on 1)

The method of claim 1, wherein the allocating the DSN access requests of the DS processing unit further comprises:
for a write request of the DSN access requests:
allocating, by the process balancing module, a unity matrix multiplication to a first active DS processing unit of the one or more active DS processing units, wherein the first active DS processing unit generates a first subset of encoded data slices of a set of encoded data slices by matrix multiplying a unity matrix of an encoding matrix with a data matrix, wherein a data segment of a data object is divided into data blocks that are arranged into the data matrix;
allocating, by the process balancing module, first redundancy matrix multiplication to a second active DS processing unit of the one or more active DS processing units, wherein the second active DS processing unit generates a first redundancy encoded data slice of the set of encoded data slices by matrix multiplying a first redundancy row of the encoding matrix with the data matrix; and
allocating, by the process balancing module, second redundancy matrix multiplication to a third active DS processing unit of the one or more active DS processing units, wherein the third active DS processing unit generates a second redundancy encoded data slice of the set of encoded data slices by matrix multiplying a second redundancy row of the encoding matrix with the data matrix.

### Claim 9 (depends on 1)

The method of claim 1, wherein the allocating the DSN access requests of the DS processing unit further comprises:
allocating, by the process balancing module, the DSN access requests of the DS processing unit to one of the active DS processing units when the one of the active DS processing units is part of a common local area network with the DS processing unit.

### Claim 10

A computer readable memory comprises:
a first memory that stores operational instructions that, when executed by a dispersed storage (DS) processing unit of a plurality of DS processing units of a dispersed storage network (DSN), causes the DS processing unit to:
identify a DSN operation to be performed that will adversely interfere with processing of DSN access requests;
send a suspension request to a process balancing module of the DSN, wherein the suspension request is for temporarily suspending processing of DSN access requests; and
a second memory that stores operational instructions that, when executed by the process balancing module, causes the process balancing module to:
determine whether sufficient processing resources of active DS processing units of the plurality of DS processing units are available for processing DSN access requests on behalf of the DS processing unit; and
when determined that sufficient processing resources are available:
grant the suspension request; and
allocate DSN access requests of the DS processing unit to one of more of the active DS processing units.

### Claim 11 (depends on 10)

The computer readable memory of claim 10 further comprises:
a third memory that stores operational instructions that, when executed by the DS processing unit, causes the DS processing unit to:
execute the DSN operation; and
upon completion of execution of the DSN operation, send a return notification to the process balancing module; and
a fourth memory that stores operational instructions that, when executed by the process balancing module, causes the process balancing module to:
in response to the return notification, resume allocation of the DSN access requests of the DS processing unit to the DS processing unit.

### Claim 12 (depends on 10)

The computer readable memory of claim 10 further comprises:
the DSN operation including one or more of garbage collection, software update, a system administration operation, and a diagnostic operation; and
the DSN access requests including two or more of a read request, a write request, a rebuild request, a list request, a delete request, and a modify request.

### Claim 13 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to:
when determined that sufficient processing resources are not available, temporarily deny the suspension request until sufficient processing resources become available.

### Claim 14 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to determine that sufficient processing resources are available by:
determining a duration for which the DS processing unit will be unavailable for processing the DSN access requests of the DS processing unit;
estimating processing requirements for processing the DSN access requests of the DS processing unit;
determining a number of other DS processing units of the plurality of DS processing units that are currently in a temporary suspension mode;
estimating processing requirements for processing other DSN access requests by the active DS processing units during the duration; and
determining processing capabilities of the active DS processing units.

### Claim 15 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to allocate the DSN access requests of the DS processing unit by:
allocate the DSN access requests of the DS processing unit to the active DS processing units in accordance with a load balancing function.

### Claim 16 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to allocate the DSN access requests of the DS processing unit by:
allocating read requests to a first active DS processing unit of the one or more active DS processing units;
allocating write requests to a second active DS processing unit of the one or more active DS processing units;
allocating list requests to a third active DS processing unit of the one or more active DS processing units; and
allocating rebuild support requests to a fourth active DS processing unit of the one or more active DS processing units.

### Claim 17 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to allocate the DSN access requests of the DS processing unit by:
for a write request of the DSN access requests:
allocating a unity matrix multiplication to a first active DS processing unit of the one or more active DS processing units, wherein the first active DS processing unit generates a first subset of encoded data slices of a set of encoded data slices by matrix multiplying a unity matrix of an encoding matrix with a data matrix, wherein a data segment of a data object is divided into data blocks that are arranged into the data matrix;
allocating first redundancy matrix multiplication to a second active DS processing unit of the one or more active DS processing units, wherein the second active DS processing unit generates a first redundancy encoded data slice of the set of encoded data slices by matrix multiplying a first redundancy row of the encoding matrix with the data matrix; and
allocating second redundancy matrix multiplication to a third active DS processing unit of the one or more active DS processing units, wherein the third active DS processing unit generates a second redundancy encoded data slice of the set of encoded data slices by matrix multiplying a second redundancy row of the encoding matrix with the data matrix.

### Claim 18 (depends on 10)

The computer readable memory of claim 10, wherein the second memory further stores operational instructions that, when executed by the process balancing module, causes the process balancing module to allocate the DSN access requests of the DS processing unit by:
allocating the DSN access requests of the DS processing unit to one of the active DS processing units when the one of the active DS processing units is part of a common local area network with the DS processing unit.