HP StorageWorks Storage Mirroring user's guide (T2558-96073, February 2008)

15 - 1
15 X Managing Data Transmission
Managing 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 14-25 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.
Scheduling transmission criteria
Using the Connection Manager Transmit tab, you can set start and stop criteria along with a schedule window.
1. Right-click the connection on the right pane of the Management Console and select Connection Manager.
2. Select the Transmit tab. The Transmit tab contains three limit types: Start, Stop, and Window. The transmission
options for each limit type are displayed by highlighting a selection in the
Limit Type box.
NOTE: If you have multiple connections to the same target, all connections will be paused and resumed.
NOTE: Storage Mirroring checks the schedule once every second, and if a user-defined criteria is met, transmission
will start or stop, depending on the option specified.
Scheduled transmission criteria is a per target option. All connections to the target will have the same
scheduled transmision configuration.