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

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4. When you schedule transmission start criteria, transmission will start when the criteria is met
and will continue until the queue is empty or a transmission stop criteria is met. Select the Start
option in the Limit Type box.
Define the start options for Storage Mirroring transmission by using any combination of the
following options.
 Transmission session start—This option establishes a date and time of the day to begin
transmitting data. For example, you may want to specify a transmission time that corresponds
to a low bandwidth usage time. Once started, Storage Mirroring will continue to transmit data
until the queue is empty or until another limitation stops the transmission. Specify a Date and
Time to start transmitting data. The down arrow next to the date field displays a calendar
allowing easy selection of any date. The time field is formatted for any AM or PM time.
 Session Interval—This option begins transmitting Storage Mirroring data at specified
intervals of time. This option is used in conjunction with Transmission session start. For
example, if the Session Interval is set to repeat transmission every 30 minutes and the
Transmission session start is set to begin transmitting at 10 p.m., if the queue is emptied
at 10:20 the transmission will stop. The start criteria is again met at 10:30 and Storage
Mirroring will begin transmitting any new data in the queue. Specify an interval for additional
transmissions by indicating a length of time and choosing minutes, hours, or days.
 Queue Threshold (percentage) and Queue threshold (bytes)—If the allocated amount
of queue disk space is in use, Storage Mirroring cannot continue to queue data causing an
auto-disconnect and the potential for loss of data. To avoid using the entire queue, you can
configure Storage Mirroring to begin transmitting data to the target when the queue reaches
a certain point. This point can be defined as a percentage of the disk queue that must be in
use or the number of bytes in the disk queue. For example, if you specify 40%, when 40% of
the queue is in use, Storage Mirroring initiates the transmission process and sends the data
in the queue to the target machine. The transmission stops when the queue is empty or a
Storage Mirroring stop transmission criteria is met. Or you might set a queue threshold of 500
MB. Storage Mirroring will wait until there is 500 MB of data in the queue and then begin
transmitting the data. Like other start criteria, Storage Mirroring continues transmitting until
the queue is empty or a Storage Mirroring stop criteria is met. Specify a percentage of the disk
queue and system memory that must be in use to initiate the transmission process, and/or
specify the number of bytes that must be in the source queue and system memory to initiate
the transmission process.
NOTE: A Transmission Session Start setting will override any other start criteria. For
example, if you set the Transmission Session Start and the Queue
Threshold, transmission will not start until you reach the indicated start time.