ZyXEL Communications NSA-2401 User Manual page 174

Chapter 8 Sharing Screens
Share
A share is a set of access permissions mapped to a specific folder on a volume. It is equivalent
to the Windows concept of a shared folder. You must have an internal volume before you can
create shares.
Volume
A volume is a storage area on a single disk or spread across a number of disks (typically
known as a disk array, or RAID) within a single file system.
XFS
XFS is journaled file system that allows for files as large as 16 terabytes. Due to the system's
design, it does not easily support snapshots. Instead, it was designed with the intention that a
logical volume manager would handle the snapshot/snapshot restoration process. The NSA-
2401 utilizes XFS for its internal file system.
Logical Volume
A logical volume is the portion of a physical hard disk drive that allows data to be written and
read. It is represented in your computer's operating system as a drive with a letter and is sub-
divided into its component files and folders. For example, on a typical home computer the
logical volume that exists on the hard drive that hosts the Windows operating system is most
often labeled the "C" drive. A physical hard disk drive can contain a single logical volume or
it can be partioned into multiple logical volumes. Furthermore, with the assistance of a logical
volume manager, a logical volume can actually span multiple physical hard disk drives.
Logical Volume Manager
A logical volume manager is tool that allows system administrators greater flexibility in
setting up and managing their system's storage allocation. With it, an administrator can create,
delete, move and resize any number of logical volumes at will.
Snapshot
A snapshot is a "point-in-time" copy of data on a logical volume. Later, as new snapshots of
the volume are made, only those bits of data that have changed from the original snapshot are
duplicated. This allows a system to create instant backups on the fly without requiring a user to
stop working or temporarily abandon the machine. Moreover, snapshots take up a fraction of
the space of traditional full-volume backups.
Network-Attached Storage (NAS)
A NAS is basically a computer that is connected to a network and which provides additional
storage capabilities to users and groups. NAS solutions most often serve as backup
destinations because they come with multiple hard disk drives and numerous redundancy
features in case any given drive fails.
Access Control List (ACL)
This is a list of read/write permissions associated with specific files and/or folders. Account
names added to the list are linked to the files and folders that they are allowed to access, along
with what kinds of actions they are allowed to perform with those files and folders.
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