Hesela / Structured knowledge

Storage Knowledge Corpus

Storage definitions, connected to their evidence.

871 terms · Page 1 of 30

A-Z

  1. Term

    3D NAND

    Flash memory that stacks cells vertically in layers to increase density without shrinking planar features alone.

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  2. Term

    3D XPoint

    A cross-point non-volatile memory technology announced by Intel and Micron, distinct from NAND flash in cell physics.

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  3. Term

    4Kn native sectors

    4Kn exposes 4096-byte logical sectors and 4096-byte physical sectors without 512-byte sector emulation.

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  4. Term

    512e emulation

    512e exposes 512-byte logical sectors over 4096-byte physical sectors.

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  5. Term

    Acting set (Ceph)

    In Ceph, the acting set is the ordered OSD list responsible for a placement group at a particular map epoch.

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  6. Term

    Active LBA range

    The specified logical-block address interval available to a storage test or its preparation workload.

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  7. Term

    Active-zone limit

    An active-zone limit caps the zones simultaneously in implicitly open, explicitly open or closed states in a zoned namespace.

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  8. Term

    Adaptive Read-Retry

    Adaptive Read-Retry selects shorter NAND precharge timing from profiled conditions while reserving error-correction margin.

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  9. Term

    Adaptive Replacement Cache

    Adaptive Replacement Cache adjusts a recency/frequency balance using resident lists and nonresident histories.

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  10. Term

    Adaptive replica selection

    Adaptive replica selection routes a request among eligible data replicas using changing performance or load information rather than a fixed choice.

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  11. Term

    Adaptive scrubbing

    Adaptive scrubbing adjusts the rate or schedule of proactive storage verification in response to observed conditions or estimated error risk.

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  12. Term

    Additional sense code

    The additional sense code (ASC) is an eight-bit SCSI sense-data field that refines the sense key and is interpreted together with its qualifier.

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  13. Term

    Additional sense code qualifier

    The additional sense code qualifier (ASCQ) is an eight-bit SCSI sense-data field interpreted with the ASC to identify a more specific condition.

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  14. Term

    Adjacent-track interference (ATI)

    Adjacent-track interference is degradation of recorded HDD data caused by writes on a neighboring track.

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  15. Term

    Advanced Format (4K)

    Advanced Format is a disk-sector architecture expanded beyond legacy 512-byte sectors, with 512e and 4Kn as its familiar 4K variants.

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  16. Term

    Advisory file lock

    An advisory file lock coordinates access among cooperating participants without itself preventing access that bypasses the locking protocol.

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  17. Term

    AHCI

    AHCI is a standardized register and memory-structure interface through which host software controls a SATA host bus adapter.

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  18. Term

    Air-gapped backup

    Offline copies physically isolated from production networks to resist ransomware.

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  19. Term

    All-flash array

    A storage array built entirely from flash modules without HDD tiers.

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  20. Term

    ALUA

    Asymmetric Logical Unit Access is the SCSI mechanism for reporting logical-unit access states through target port groups.

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  21. Term

    ANA group

    An ANA group is a set of NVMe namespaces whose ANA access states change together for a given controller.

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  22. Term

    Annual replacement rate

    Annual replacement rate (ARR) counts recorded device replacements relative to device exposure, scaled to one year.

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  23. Term

    Annualized failure rate (AFR)

    Annualized failure rate (AFR) expresses observed failures relative to drive-time exposure, scaled to a year, and is not inherently a one-year failure probability.

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  24. Term

    Anti-entropy repair

    Anti-entropy repair compares replica state over a selected scope and synchronizes differences to reduce divergence.

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  25. Term

    Apache Parquet

    Apache Parquet is a column-oriented file format that organizes data into row groups, column chunks and encoded pages.

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  26. Term

    Application quiescing

    Application quiescing is application-specific preparation and temporary restriction of writes to establish a defined state for snapshot or backup capture.

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  27. Term

    Application-consistent snapshot

    An application-consistent snapshot captures an application's data through a coordinated procedure that satisfies that application's consistency requirements.

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  28. Term

    Archive member

    An archive member is an individual stored entry with its own metadata and, where applicable, payload, whose name need not be unique within an archive.

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  29. Term

    Areal density

    Bits stored per unit of disk surface area, the central metric driving HDD capacity growth.

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  30. Term

    ArmorCache

    ArmorCache is an HDD cache-protection feature that uses OptiNAND flash to preserve buffered user writes during emergency power loss on supported drives.

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