Storage - Mirror Options

Mirror Mode

When you only have one device inside your backup storage group and one device inside your mirror group, it does not matter which mirror mode you select.

But, when you have a mirror group that consists of more than one device/location, you can choose to correlate the mirror storage devices to a corresponding backup storage device/location; which is referred to as an Interlocked Mirror. Or, you can choose to use the mirror in an Ad-hoc mode, in which the mirroring process will replicate the files form any of the backup storage drives to any of the mirror drives based on available free space.

• When Should I Use Interlocked Mode Mirrors?
  If you want to have a 1-to-1 correspondence between each device in the backup storage group to a corresponding mirror device, you should select interlocked mode. The key advantage of using interlocked mirrors is if a backup storage device fails, you can replace the failed backup storage device with its corresponding mirror device.
   
• When Should I Use Ad-Hoc Mode Mirrors?
  If it is not convenient or practical for you to have a 1-to-1 correspondence between your backup storage group and mirror group devices, then select the Ad-Hoc mode. For example, your backup storage group device could be rather expensive and it is impractical to duplicate this in its entirety for the mirror. In this case, you may choose to use lower-cost storage for the mirror, and as a result, you might have more mirror devices than backup storage devices. An example of this would be if you plan to use a SAN or NAS device as your backup storage, but want to use a group of USB drives for portability in your mirror group.
   
• What Happens If I Change Mirror Modes?
  In the event that you change the mirror mode from one method to the other, Backup for Workgroups will perform a re-sync if necessary. This re-sync will realign the mirror storage to the backup storage; which may be very time-consuming.

Throttle

The goal of using the throttle option is to give you control over the speed at which the mirroring process occurs. By default, the mirroring process will consume as much bandwidth as available between the Backup Server and the mirror device. If you want to prevent the mirroring process from consuming all the available bandwidth, use the "Limit the mirror update rate" option and specify a rate appropriate for your connection. For example, if your mirror device is off-site, you may want a throttle speed that is half of your Internet link speed, to prevent the mirror process from consuming your Internet link. 

Blackout

Use the blackout feature to prevent the mirror from consuming excess resources during business hours. For example, if the mirror is located off-site, and you want to prevent the mirroring process from consuming your Internet link during business hours, you can set a blackout period to keep the mirroring process quiet.