Hesela / Structured knowledge

Storage Knowledge Corpus

Storage definitions, connected to their evidence.

866 terms · Page 19 of 29

A-Z

  1. Term

    Persistence domain

    A persistence domain is the set of components whose stored contents are guaranteed to survive a specified failure under the platform's operating contract.

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  2. Term

    Persistence ordering

    Persistence ordering is a constraint on the order in which updates become durable, rather than merely the order in which an application issues them.

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  3. Term

    Persistent memory

    Persistent memory is nonvolatile storage exposed through a memory-addressable interface, with durability governed by the platform's persistence contract.

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  4. Term

    Phase-change memory (storage)

    Phase-change memory (PCM) stores a bit as the resistance of a small volume of chalcogenide alloy: a short, high current pulse melts and quenches it into a high-resistance amorphous state, a longer, moderate pulse crystallises it into a low-resistance state, and a small current reads the resistance without changing it.

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  5. Term

    Phi accrual failure detector

    A phi accrual failure detector expresses suspicion as the negative base-10 logarithm of an estimated heartbeat inter-arrival tail probability.

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  6. Term

    Physical journaling

    Physical journaling records modified on-disk representations, such as metadata buffer contents or changed regions, for recovery.

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  7. Term

    Physical sector

    A physical sector is the device-level data unit whose reported size describes physical read/write granularity rather than logical addressing.

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  8. Term

    Pipelined Read-Retry

    Pipelined Read-Retry overlaps NAND retry sensing with transfer and decoding of earlier attempts.

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  9. Term

    Placement group (Ceph)

    In Ceph, a placement group is a logical grouping of objects within a pool that share storage placement and are managed together for replication and recovery.

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  10. Term

    Planar NAND

    Planar (2D) NAND is flash memory in which the cells are built in a single layer on the silicon surface, the layout that 3D NAND replaced as a way to raise bit density.

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  11. Term

    PLC

    Penta-level cell (PLC) NAND encodes five bits per cell using thirty-two threshold-voltage states.

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  12. Term

    Point-in-time recovery

    Point-in-time recovery restores a database to a selected historical state by applying retained transaction-log history to a suitable backup.

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  13. Term

    Poisson rate model

    A Poisson rate model represents an event count over a specified exposure by a Poisson distribution with mean equal to the event rate multiplied by that exposure.

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  14. Term

    Pole erasure

    Pole erasure is unintended disturbance of recorded data by a write pole's residual magnetic field after the write current has stopped.

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  15. Term

    POSIX_FADV_DONTNEED

    POSIX_FADV_DONTNEED is a file-access advice value requesting release of cached data that the application does not expect to access soon.

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  16. Term

    POSIX_FADV_NOREUSE

    POSIX_FADV_NOREUSE is a file-access advice value indicating that the application does not expect to reuse the specified data.

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  17. Term

    POSIX_FADV_WILLNEED

    POSIX_FADV_WILLNEED is file-access advice announcing that an application expects to read a specified range soon.

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  18. Term

    posix_fallocate

    A POSIX library function that reserves storage for a file byte range and reports failure by returning an error number directly.

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  19. Term

    Power loss protection

    Power-loss protection is a set of hardware and firmware measures intended to preserve specified storage-device data and internal state when external power is unexpectedly removed.

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  20. Term

    Power-aware coding

    Power-aware coding uses redundancy to serve selected reads without activating the disks containing the requested data.

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  21. Term

    Power-on hours

    Power-on hours is accumulated powered-operation time reported for a device, interpreted according to that device's counter and interface semantics.

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  22. Term

    Powersafe overwrite

    Powersafe overwrite is the storage property that an interrupted file write leaves bytes outside its requested range unchanged.

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  23. Term

    Precision

    Precision is the fraction of positive predictions that match observed positive outcomes at a specified decision threshold.

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  24. Term

    Prediction cadence

    Prediction cadence is the schedule or interval at which a prediction system produces successive predictions for the same monitored entity.

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  25. Term

    Prediction horizon

    A prediction horizon is the future interval after a prediction time in which a specified target event is evaluated.

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  26. Term

    Prefetch trigger distance

    Prefetch trigger distance specifies how far before the end of an already-prefetched sequence the next prefetch is initiated.

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  27. Term

    Prefetch wastage

    Prefetch wastage is the eviction of prefetched data before its first demand access.

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  28. Term

    Prefix Bloom filter

    A Bloom filter built over extracted key prefixes rather than only whole keys, allowing negative membership tests for those represented prefixes.

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  29. Term

    Prefix extractor

    A key transformation with a defined input domain that produces the prefix used for prefix-based indexing or filtering.

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  30. Term

    Prefix-preserving crash consistency

    A recovery contract in which surviving updates form a prefix of the specified write order, including all writes covered by the last successful flush.

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