Home / Glossary
NAS and storage terms explained
Understand RAID, drives, networking, backup, filesystems and storage terminology.
#
10GbE
10GbE means 10 Gigabit Ethernet, a wired networking standard with a nominal link speed of up to 10 gigabits per second. Actual throughput depends on the hardware, connection type, network, and workload.
Learn more2.5GbE
2.5GbE is an Ethernet connection standard with a link speed of up to 2.5 gigabits per second. On a NAS, it can provide more network capacity than 1GbE when the rest of the network supports it.
Learn moreB
C
D
E
ECC memory
ECC memory uses error-correcting code to detect and, in some cases, correct certain memory errors. On a NAS, it can help reduce the effect of memory faults, but the NAS platform must support it.
Learn moreexpansion unit
An expansion unit is hardware that adds storage drive capacity to a larger storage system. On NASFit, the term appears with hot-replace LVD SCSI drive bays and one or more hot-plug power supply modules.
Learn moreH
hot spare
A hot spare is an unused drive reserved to replace a failed drive in a storage array, usually through an automatic rebuild. It helps reduce the time an array operates with reduced redundancy.
Learn morehot-swap
Hot-swap means a component can be removed and replaced while the system remains powered, subject to the product’s supported hardware and procedures.
Learn moreI
J
L
N
NAS HDD
A NAS HDD is a hard disk drive marketed or specified for use in a network-attached storage system. It provides internal storage for shared files, backups, media, and other NAS data.
Learn moreNAS SSD
A NAS SSD is a solid-state drive selected for use in network-attached storage. It uses flash storage rather than spinning disks, but the label alone does not confirm compatibility, endurance, or performance.
Learn moreNFS
NFS (Network File System) lets compatible computers access shared folders over a network. On NAS products, the specification usually identifies NFS support and may also state the supported version or transport.
Learn moreNVMe cache
An NVMe cache uses fast NVMe SSDs to temporarily hold frequently accessed NAS data, potentially reducing access delays for some workloads. It is not the same as adding permanent storage capacity.
Learn moreR
RAID
RAID combines multiple drives to improve capacity, performance, or resilience through striping, mirroring, or parity. It is redundancy, not a backup.
Learn moreRAID 1
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 10
RAID 10 combines mirrored drive pairs with data striping, providing redundancy and potentially improved storage performance while using about half of the raw drive capacity.
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.
Learn moreRAID 6
RAID 6 is a storage layout that uses dual parity to protect data if up to two drives in the array fail. It improves fault tolerance but reduces usable capacity compared with single-parity RAID.
Learn moreS
SHR
SHR means Synology Hybrid RAID, a Synology storage technology that combines drives into a redundant storage pool and can simplify use of different-capacity drives.
Learn moreSMB
SMB (Server Message Block) is a network file-sharing protocol. On NAS products, it commonly lets computers and other clients access shared folders over a local network.
Learn moreSMR
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 moresnapshot
A snapshot is a point-in-time record of NAS data that can help you view or restore an earlier state after accidental changes, deletion, or other data problems.
Learn moresnapshot replication
Snapshot replication copies point-in-time snapshots from one NAS system, volume, or shared folder to another location. It can help preserve recoverable versions if the primary data is damaged or unavailable.
Learn moreSSD cache
SSD cache uses solid-state storage to keep frequently accessed NAS data or metadata readily available. It can improve responsiveness for some workloads, but its effect depends on the NAS, drives, settings, and access patterns.
Learn more