HP StorageWorks Storage Mirroring for Linux User's Guide (T2558-96317, June 2009)

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Data Transmission
Storage Mirroring data is continuously transmitted to the target
machine. Although the data may be queued if the network or target
machine is slow, the default transmission setting is to transmit the
data as soon as possible. You can modify the tranmission to suit your environment.
 Manual transmission control—You can maintain the source/target connection, but still control
the transmission of data across the network by using the manual transmission controls. If
tranmission is paused, the data is queued on the source until you manually restart the
transmission.
 Manual target control—You can break the source/target connection without disconnecting the
connection, so that you can control the transmission of data across the network. You can do this
by pausing the target. If the target is paused, data is queued on the source until you manually
resume the target.
 Scheduled transmission—You can set event driven or scheduling criteria to determine when
data is transmitted. Data is queued on the source until the event or schedule is met. Also,
transmission can be stopped by using these criteria. Scheduled transmission options can be
toggled on and off, allowing you to enable them only when you need to use them.
 Bandwidth limitations—You can specify bandwidth limitations to restrict the amount of network
bandwidth used for Storage Mirroring data transmissions. Data is queued on the source until
bandwidth is available. Bandwidth limitations can be full-time or scheduled.
Controlling transmission manually
To start, pause, or resume the transmission of data from the source to the target, right-click an
established connection and select Transmit and the appropriate transmission control.
Controlling a target manually
You can break the source/target connection without disconnecting the connection, so that you can
control the transmission of data across the network. You can do this by pausing the target. If the
target is paused, data is queued on the source until you manually resume the target. For example,
you may want to pause the target while you perform a backup of the target data, and then resume
the target when the backup is complete.
While the target is paused, the Storage Mirroring source cannot queue data indefinitely. If the source
queue is filled, Storage Mirroring will automatically disconnect the connections and attempt to
reconnect them. See Configuring automatic reconnections on page 9-12 for more information.
To pause a target, right-click a target server on the left pane of the Management Console and select
Pause Target. All active connections to that target will complete the operatings already in progress.
You will see Pause Pending in the Management Console while these operations are completed. The
status will update to Paused after the operations are completed. Any new operations will be queued
on the source until the target is resumed. When you are ready to resume the target, right-click the
target and select Resume Target.
NOTE: If you have multiple connections to the same target, all connections will be paused and
resumed.