Operating System Software Owner manual

18 Limiting Throughput
“Limiting Throughput for Asynchronous Periodic Volume
Groups” (page 97)
To save on leased-line charges during synchronization,
limit throughput.
“Removing Throughput Limits” (page 98)To send as much data as possible, remove throughput
limits.
By default, Remote Copy sends data as fast as it can on all links between a Remote Copy pair.
However, this method can be expensive if you are resynchronizing asynchronous periodic volume
groups over a leased line that charges based on the bit rate used.
When you limit throughput, Remote Copy meters the data and sends it out at a rate less than or
equal to the specified limit.
Limiting Throughput for Asynchronous Periodic Volume Groups
NOTE: Throughput limits are not recommended for volume groups in synchronous mode because
limited throughput results in higher latency for host writes to the primary volumes.
1. Stop the volume groups.
# stoprcopygroup <group_name>
or:
# stoprcopygroup -pat <pattern>
• <pattern> - Pattern of volume group names to stop (for example, Group*)
2. Specify the rate of data transfer.
# setrcopytarget tput <tput_value>{g|G|m|M|k|K} <target_name>
• <tput_value> - Maximum throughput limit and size unit. By default, throughput is
measured in kilobytes per second. Optionally, you can specify the size unit (gigabytes
per second, megabytes per second, or kilobytes per second).
• <target_name> - Target name (for example, backup system name)
3. Start the volume groups.
# startrcopygroup <group_name>
or:
# startrcopygroup -pat <pattern>
Limiting Throughput for Asynchronous Periodic Volume Groups 97