Why do backups and restores use Primary LAN connection during jobs instead of using the secondary LAN or Fiber Channel Card

Note: whilst the information in this solution was originally written for customers that have a LAN technology Fiber Network, the discussion and configuration applies equally to any secondary network (LAN) used for backup purposes. As such where the diagrams show a fiber-channel card or fiber network, this represents any secondary network card or backup LAN

When communicating from server to server in any given network scenario, the method of locating the server to which the first server needs to talk to, a query will be made to a server on the network that assumes the role of DNS (Domain Name Service).  This server will then translate the name of the server that has been queried into an IP address.  This is returned to the requesting server as the location of the server that was queried.  The requesting server then uses that IP address to directly query the remote server that it is requesting to talk to.  This process is standard for any TCP / IP network topology.

There are alternate types of network media that can be used to reach servers on a network.  The table below describes a list of the possible connections.

Table 1
 

Standard	Cable Type	Maximum Length	Connector Type	IEEE Standard
10Base2	Thin Coaxial	185 Meters	BNC	803.2a
10 / 100 / 1000 BaseT	Cat 3, 4, 5, 5E Twisted Pair	100 Meters	RJ-45	803.2a
10BaseFL / FDDI	Fiber Optic / Twisted Pair (CDDI)	2000 Meters	SC / ST	803.2a / ANSI FDDI

This is only a short list of the type of network mediums available.  The most common is RJ-45 and Fiber connector types.

When Backup Exec attempts to backup a server, this occurs across the medium that the network DNS says is the way to reach the remote server.  The following steps are used to establish a connection to the source server selected for backup.
 

1.  Backup Exec makes a query to the DNS to resolve the IP address for the server selected for backup

2.  The DNS server returns the IP address

3.  Backup Exec opens a connection to the IP address on the NDMP port (default is 10000)

4.  Backup Exec establishes a port to be used for data transmission to and from the Media server and Remote server

5.  Backup begins

This is explained in the diagram listed below in Figure 1

Figure 1
 



 

Required items to use a Backup Lan over fiber-channel adaptor OR secondary NIC

1.  Install a second NIC or Fiber channel card that supports the assignment of an IP address to itself.

2.  Make sure that there are no zoning or routing restrictions that prevent one server from communicating to another via te secondary network.

3.  Configure local hosts files or DNS to use the IP addresses on the secondary NIC or fiber-channel adaptor. (Note: typically changing the DNS might affect clients and servers that need to communicate over the production network, as such local host files are the recommended option. )

4.  Confirm that the remote server(s) is/are resolved to the IP address on the secondary network
5.  Some environments will need the remote servers to resolve the Backup Exec Server on its secondary IP address, so consider using point 3 and 4 on the remote systems as well

6.  Create a backup job on the Media server to backup the remote servers.

7.  Run the backups.

This is explained in the diagram listed below in Figure 3

Figure 3
 

The above configuration (that changes DNS resolution to manage the communication between servers) is required to ensure data travels over the correct network, if you specify the option to use only a specifc interface card and have not configured local name resolution correctly, job failures may occur.  For instructions on how to configure the fiber channel cards to use an IP address, contact the manufacturer of the fiber channel card for assistance.