# US 2018/0322003 A1 · Fault isolation in transaction logs

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- Number: US 2018/0322003 A1
- Document ID: US20180322003A1
- Status: Published application
- Kind: A1
- Application number: 15/770,840
- Filed: 2016-02-26
- Published: 2018-11-08
- Earliest claimed: 2016-02-26
- Assignees: Hewlett Packard Enterprise Development LP
- Applicants: Hewlett Packard Enterprise Development LP
- Inventors: Tim Silversides
- Web page: https://patentgrep.com/patent/US20180322003A1

## CPC

- G06F 11/0745: {in an input/output transactions management context (input/output processing in general G06F13/00)}
- G06F 11/0793: {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)}
- G06F 11/1004: {to protect a block of data words, e.g. CRC or checksum (G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00)}
- G06F 11/20: using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
- G06F 11/3438: {monitoring of user actions (tracking the activity of the user H04L67/535)}
- G06F 2201/87: Monitoring of transactions
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

Examples include fault isolation in transaction logs. Some examples involve generation of a transaction log entry associated with a fault domain. The transaction log entry may comprise a transaction signature and a fault domain identifier. Based on the transaction signature, a domain sum may be computed. A determination may be made whether each transaction log entry associated with the fault domain is valid, and a valid domain sum may be computed for the fault domain based on the transaction signature of each valid transaction log entry associated with the fault domain. Based on a determination that the domain sum equals the valid domain sum, the fault domain may be recovered.

## Claims

### Claim 1

A computing device comprising:
a processor; and
a machine-readable storage medium encoded with instructions executable by the processor to provide fault isolation in a transaction log, the machine-readable storage medium comprising:
instructions to generate in the transaction log a transaction log entry for a transaction, wherein the transaction log entry comprises a transaction signature and a fault domain identifier that identifies a fault domain with which the transaction log entry is associated;
instructions to compute a domain sum for the fault domain based on the transaction signature of each transaction log entry associated with the fault domain;
instructions to determine whether each transaction log entry associated with the fault domain is valid;
instructions to compute a valid domain sum for the fault domain based on the transaction signature of each valid transaction log entry associated with the fault domain; and
instructions to determine whether the domain sum equals the valid domain sum.

### Claim 2 (depends on 1)

The computing device of claim 1, wherein the machine-readable storage medium further comprises:
instructions to mark the fault domain valid and recover the fault domain based on a determination that the domain sum equals the valid domain sum.

### Claim 3 (depends on 1)

The computing device of claim 1, wherein the machine-readable storage medium further comprises:
instructions to generate an intent record for the transaction before generating the transaction log entry for the transaction, wherein the intent record is associated with the fault domain and comprises the transaction signature and an operation identifier;
based on a determination that the domain sum does not equal the valid domain sum, instructions to compute a new valid domain sum for the fault domain based on the operation identifier of the intent record; and
instructions to determine whether the domain sum equals the new valid domain sum.

### Claim 4 (depends on 3)

The computing device of claim 3, wherein the instructions to compute the new valid domain sum further comprise:
instructions to determine whether the operation identifier of the intent record identifies an add operation or a remove operation;
instructions to add the checksum of the intent record to the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies a remove operation; and
instructions to subtract the transaction signature of the intent record from the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies an add operation.

### Claim 5 (depends on 3)

The computing device of claim 3, wherein the machine-readable storage medium further comprises:
instructions to mark the fault domain valid and recover the fault domain based on a determination that the domain sum equals the new valid domain sum.

### Claim 6 (depends on 3)

The computing device of claim 3, wherein the machine-readable storage medium further comprises:
instructions to mark the fault domain invalid and discard each transaction log entry associated with the fault domain based on a determination that the domain sum does not equal the new valid domain sum.

### Claim 7 (depends on 1)

The computing device of claim 1, wherein the instructions to generate the transaction log entry for the transaction further comprise:
instructions to build a log entry for the transaction in a local memory area; and
instructions to copy the log entry for the transaction in the local memory area to the transaction log entry for the transaction in a remote memory area.

### Claim 8 (depends on 1)

The computing device of claim 1, wherein the machine-readable storage medium further comprises;
instructions to generate the transaction log, wherein the transaction log is a global array comprising more than one fault domain, and wherein at least one of the more than one fault domain is dynamically allocated.

### Claim 9

A machine-readable storage medium encoded with instructions executable by a processor of a computing device to provide fault isolation in a transaction log, the machine-readable storage medium comprising:
instructions to generate an intent record for a transaction, wherein the intent record is associated with a fault domain and comprises a transaction signature and an operation identifier;
instructions to generate in the transaction log a transaction log entry for the transaction after generating the intent record for the transaction, wherein the transaction log entry comprises the transaction signature and a fault domain identifier that identifies the fault domain with which the transaction log entry is associated;
instructions to compute a domain sum for the fault domain based on the transaction signature of each transaction log entry associated with the fault domain;
instructions to determine whether each transaction log entry associated with the fault domain is valid;
instructions to compute a valid domain sum for the fault domain based on the transaction signature of each valid transaction log entry associated with the fault domain; and
instructions to determine whether the fault domain is valid based on the domain sum, the valid domain sum, and the intent record.

### Claim 10 (depends on 9)

The machine-readable storage medium of claim 9, wherein the instructions to determine whether the fault domain is valid further comprise:
instructions to determine whether the domain sum equals the valid domain sum;
based on a determination that the domain sum does equal the valid domain sum, instructions to mark the fault domain valid and recover the fault domain;
based on a determination that the domain sum does not equal the valid domain sum, instructions to compute a new valid domain sum for the fault domain based on the operation identifier of the intent record; and
instructions to determine whether the domain sum equals the new valid domain sum.

### Claim 11 (depends on 10)

The machine-readable storage medium of claim 10, wherein the instructions to compute the new valid domain sum further comprise:
instructions to determine whether the operation identifier of the intent record identifies an add operation or a remove operation;
instructions to add the transaction signature of the intent record to the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies a remove operation; and
instructions to subtract the transaction signature of the intent record from the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies an add operation.

### Claim 12 (depends on 10)

The machine-readable storage medium of claim 10, wherein the machine-readable storage medium further comprises:
instructions to mark the fault domain valid and recover the fault domain based on a determination that the domain sum equals the new valid domain sum; and
instructions to mark the fault domain invalid and discard each transaction log entry associated with the fault domain based on a determination that the domain sum does not equal the new valid domain sum.

### Claim 13

A method for providing fault isolation in a transaction log, the method comprising:
generating in the transaction log a transaction log entry for a transaction, wherein the transaction log entry comprises a transaction signature and a fault domain identifier that identifies a fault domain with which the transaction log entry is associated;
computing a domain sum for the fault domain based on the transaction signature of each transaction log entry associated with the fault domain;
determining whether each transaction log entry associated with the fault domain is valid;
computing a valid domain sum for the fault domain based on the transaction signature of each valid transaction log entry associated with the fault domain;
determining whether the domain sum equals the valid domain sum; and
recovering the fault domain based on a determination that the domain sum equals the valid domain sum.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
generating an intent record for the transaction before generating the transaction log entry for the transaction, wherein the intent record is associated with the fault domain and comprises the transaction signature and the operation identifier;
based on a determination that the domain sum does not equal the valid domain sum, computing a new valid domain sum for the fault domain based on the operation identifier of the intent record;
determining whether the domain sum equals the new valid domain sum;
recovering the fault domain based on a determination that the domain sum equals the new valid domain sum; and
discarding each transaction log entry associated with the fault domain based on a determination that the domain sum does not equal the new valid domain sum.

### Claim 15 (depends on 4)

The method of claim 4, wherein computing the new valid domain sum further comprises:
determining whether the operation identifier of the intent record identifies an add operation or a remove operation;
adding the transaction signature of the intent record to the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies a remove operation; and
subtracting the transaction signature of the intent record from the valid domain sum to compute the new valid domain sum based on a determination that the operation identifier of the intent record identifies an add operation.