How to schedule the bandwidth limit in a scenario
CA ARCserve RHA enables you to control the size of the allowed incoming bandwidth on the replica host. For each day of the week, you can either define one limit size that will apply to all hours of the day, or you can specify different values for different hours. By using the bandwidth scheduler, you can decrease the bandwidth size on busy hours and increase it on off-peak hours in order to optimize your bandwidth resources.
■ The bandwidth limit that you set for one replica host does not apply to other replica hosts that reside in the same replication tree. You need to change each replica host definition separately.
■ It is important to note, if you need true high availability at all times you should make sure the bandwidth isn't lowered too much during production hours to the point where more changes are occuring to the active server than we have bandwidth available to send them. In this case you would start spooling the additional changes on the master because of the low bandwidth bottleneck. If the master were to suddenly go down for any reasson and you needed to switchover your replica would then be missing data. So if you lower the bandwidth during production hours and this causes the active server's spool to grow during replication mode you may need to increase the bandwidth to a higher value to compensate for that issue and keep the spools empty and keep true high availability in tact.
■ The default value for the bandwidth limit option is 'Unlimited'. It means that no restriction is imposed on the bandwidth between the master and the replica.
To schedule the bandwidth limit:
1. On the replica properties list, open the replication group. On the bandwidth limit property, click the value box that contains the unlimited default value.
The bandwidth scheduler dialog opens.
2. Set the daily schedule for incoming bandwidth size according to the following guidelines:
■ On the Day/Hours table, select one or several rectangles for the period in the day for which you want to define a certain bandwidth size.
Note: You can set more than one rectangle simultaneously by clicking and dragging the mouse. You can also use the Ctrl and Shift keys to set several dates at once.
■ Once the rectangles are marked, from the Bandwidth Values section click the values (in Kbps) you want to apply on the selected hours.
The rectangles of the selected hours now contain the value you selected.
3. To apply similar bandwidth to all days, apply the bandwidth to Sunday and click Apply the Sunday's value to all work days or repeat the above process for all hours. If no size is defined for a specific hour, the Unlimited default value is applied to it.
Note: To clear the setting, click the Reset button.
4. Once you finished defining the Bandwidth Scheduler, click OK to save your setting and close the dialog.
The setting you defined now appears in the Bandwidth Limit value box in the Properties list.
5. To save your setting, click the Save button on the standard toolbar.