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NAS and storage terms explained
Understand RAID, drives, networking, backup, filesystems and storage terminology.
CMR
CMR (conventional magnetic recording) stores hard-drive tracks without the overlapping layout used by SMR. It can be a useful recording-technology label when comparing drives for write-heavy workloads.
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RAID combines multiple drives to improve capacity, performance, or resilience through striping, mirroring, or parity. It is redundancy, not a backup.
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RAID 1 mirrors data across two drives, so one drive can fail without immediately making the data unavailable. It reduces usable capacity and is not a substitute for a backup.
Learn moreRAID 5
RAID 5 combines data striping with distributed parity, allowing an array to keep operating after one member drive fails. It needs at least three drives and does not replace a backup.
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SMR (shingled magnetic recording) overlaps data tracks to increase storage density. This can make some random-write workloads and rebuilds more involved than with conventional magnetic recording.
Learn moreZFS
ZFS is a filesystem and storage-management system used on some NAS devices. It combines file storage with features such as checksums, snapshots, storage pools, and RAID-Z, depending on the product.
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