Overland Storage SnapServer Administrator's Manual page 259

SnapServer 7.0 Administrator's Guide
NL_port
A Node Loop port is capable of arbitrated loop functions and protocols. An NL_Port connects
via an arbitrated loop to other NL_Port and at most a single FL_Port. NL_Ports handle
creation, detection, and flow of message units to and from the connected systems. NL_Ports
are end ports in virtual point-to-point links through a fabric, for example NL_Port to F_Port
to F_Port to N_Port using a single Fibre Channel fabric switch. In the absence of a fabric
switch FL_Port, NL_Ports can communicate with other NL_Ports in virtual point-to-point
links through a FC-AL open loop circuit often through FC-AL (Arbitrated Loop) hub or loop
switch devices.
Node
Any device, including servers, workstations, or tape devices, that are connected to a
network; also the point where devices are connected.
Node Name
This is an eight-byte, 16-character hexadecimal number, uniquely identifying a single fibre
device. It incorporates the World Wide Name and two additional bytes that are used to
specify the format. In a host system with multiple FC ports, all adapters typically use the
same Node Name, but unique Port Names.
NTFS
Short for New Technology File System. The standard file system used by Windows NT and
later versions of the Windows operating system.
NTP
Short for Network Time Protocol. A protocol for synchronizing the system clocks of
computers over a packet-switched network.
NVRAM
Abbreviation of Non-Volatile Random Access Memory, a type of memory that retains its
contents when power is turned off.
ODA
The Overwrite Data Area is an internal storage area on an array that is dedicated to storing
data from a snapshot logical drive. The data stored on the ODA is the data from the logical
drive that needed to be overwritten after a snapshot was initiated. The ODAs are mapped
on top of internal logical drives. An ODA cannot be accessed externally through a host LUN;
it is only accessed internally.
ODA Stripe Size
The read/write block size that the system will use when copying data from the original
logical drive to the ODA.
Orphan
A disk drive that has become disconnected from its RAID either by accidental removal of
the drive or the intermittent failure of the drive.
Parity
Error correction data. RAIDs 5, 6, 50, and 60 store equal portions of each file on each disk
and distributes parity information for each file across all disks in the group. This
distributed parity allows the system to recover from a single disk drive failure.
10400317-001 10/2011
©2010-11 Overland Storage, Inc.
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