Administrator Guide

For example, in banking, two withdrawals from a checking account that started at the same time must not overlap; therefore,
they are processed synchronously.
T
throughput
1. The number of bits, characters, or blocks passing through a data communication system or portion of that system.
2. The maximum capacity of a communications channel or system.
3. A measure of the amount of work performed by a system over a period of time. For example, the number of I/Os per day.
tool command language (TCL)
A scripting language often used for rapid prototypes and scripted applications.
transfer size
The size of the region in cache used to service data migration. The area is globally locked, read at the source, and written at the
target. Transfer size can be as small as 40 K, as large as 128 M, and must be a multiple of 4 K. The default value is 128 K.
A larger transfer size results in higher performance for the migration, but may negatively impact front-end I/O. This is especially
true for metro node Metro migrations. Set a large transfer-size for migrations when the priority is data protection or migration
performance.
A smaller transfer size results in lower performance for the migration, but creates less impact on front-end I/O and response
times for hosts. Set a smaller transfer-size for migrations when the priority is front-end storage response time.
transmission control protocol/Internet protocol (TCP/IP)
The basic communication language or protocol used for traffic on a private network and the Internet.
U
uninterruptible power supply (UPS)
A power supply that includes a battery to maintain power in the event of a power failure.
universal unique identifier (UUID)
A 64-bit number used to uniquely identify each metro node director. This number is based on the hardware serial number
assigned to each director.
V
virtualization
A layer of abstraction that is implemented in software that servers use to divide available physical storage into storage volumes
or virtual volumes.
virtual volume
Unit of storage presented by the metro node front end ports to hosts. A virtual volume looks like a contiguous volume, but can
be distributed over two or more storage volumes.
W
wide area network (WAN)
A geographically dispersed telecommunications network. This term distinguishes a broader telecommunication structure from a
local area network (LAN).
world wide name (WWN)
A specific Fibre Channel Name Identifier that is unique worldwide and represented by a 64-bit unsigned binary value.
Glossary
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