CLI Guide

Table Of Contents

About transfer-size

Transfer-size is the size of the region in cache used to service the migration. The area is globally locked, read at the source, and

written at the target.

Transfer-size can be as small 40 K, as large as 128 M, and must be a multiple of 4 K. The default recommended 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.

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 large transfer-size for migrations when the priority is data protection or migration performance. Set a smaller transfer-size

for migrations when the priority is front-end storage response time.

Factors to consider when specifying the transfer-size:

● For metro node Metro configurations with narrow inter-cluster bandwidth, set the transfer size lower so the migration does

not impact inter-cluster I/O.

● The region specified by transfer-size is locked during migration. Host I/O to or from that region is held. Set a smaller

transfer-size during periods of high host I/O.

● When a region of data is transferred, a broadcast is sent to the system. Smaller transfer-size mean more broadcasts, slowing

the migration.

Examples

VPlexcli:/> batch-migrate start --file BS0_19 --transfer-size 1M