Separation of networks:  Again, you must separate your external customer management network from your backup FSI network. An important step is to configure the ProtecTIER network so that each virtual interface (IP) is on a different network and preferably a different VLAN in a multitier network infrastructure. 

If you use the configuration that is shown in Table 5-1 on page 69, all of your backup servers connect to the IP of the ProtecTIER application virtual interface fsi1. The default load-balancing (LB) method of round robin (RR) mode 1 works without special network infrastructure hardware requirements. This LB mode permits, depending on your network infrastructure, a unidirectional bandwidth increase. 

This configuration means that, from the perspective of a single data stream that flows outbound from a ProtecTIER server, you can potentially benefit from up to 4 Gb of bandwidth, which is essentially the combined throughput of all four aggregated interfaces. It also means that restoring data from your ProtecTIER server to your backup server could be fast. For further details about port aggregation, see Chapter 3, “Networking essentials” on page 37. 

Backing up your data creates a data stream that is directed toward the ProtecTIER server. Single data streams directed toward a ProtecTIER server do not benefit from the potential bandwidth increase when you use the round-robin LB method in this example. 

To fully use the ProtecTIER server resources in this configuration, you must use multiple backup servers that back up to their respective file systems on the ProtecTIER server. To further optimize the potential throughput of single backup server environments, you must understand the link aggregation methods that can be used for load balancing and increasing throughput, as listed in Table 3-1 on page 42. 

## 5.1.4 Replication 

You can use ProtecTIER to define replication policies to replicate a file system’s directories and all the objects that are contained in these directories recursively to remote ProtecTIER repositories without any disruption to the operation of the file system as a target for backup. It is possible to define up to 64 source directories per one replication policy, and to define up to three remote ProtecTIER destinations. 

The replicated data in the remote destination can be easily used to restore data in the case of a Disaster Recovery (DR), or in the case of a DR test (without any interruption to the backup and replication procedures). 

An important task is to enable the ProtecTIER system to supervise all the changes that are made to a directory, or to a set of directories, that is constantly defined in a replication policy. Therefore, you should not disable a replication policy unless this policy is no longer considered relevant. 

If maintenance is scheduled for the network that is used for replication, a possibility (although not mandatory) is to suspend the replication to a specific destination. Suspending replication enables the ProtecTIER system to continue supervising all of the changes, but it does not attempt to send the replication data through the network for the time that is defined by the suspend operation. The suspend operation is limited in time, with a maximum suspend time of 72 hours. 

