IBM E16RMLL-I - Tivoli Storage Manager, Implementation Manual

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Chapter 2. Implementation planning
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In installations where network connectivity is slow or expensive, placing a Tivoli
Storage Manager server close to the clients usually makes sense. For example,
for a business that has multiple file servers in each of a number of cities
interconnected by a slow network, it may be appropriate to install a Tivoli Storage
Manager server in each city.
2.6.2 Disadvantages of multiple servers
Multiple servers increase costs. Two small server CPUs may be more expensive
than one larger CPU of the same power. Where one automated tape library may
be enough, multiple servers may require multiple automated libraries. Every
Tivoli Storage Manager server requires a Tivoli Storage Manager server license.
Management of a multiple-server environment is more complex, costly, and time
consuming than a single environment. Installation and maintenance procedures
have to be repeated on each server. Confusion about where data is stored, in the
event of a restore, may result. Some of these disadvantages can be reduced by
using the Enterprise Administration feature.
2.7 Network
The network connection plays an integral part in providing service to the client. If
the other components of the solution have been correctly sized, it will often turn
out that the network is the performance bottleneck. The network typically
consists of a combination of network interface cards, hubs, routers, gateways,
wire, and software. Tivoli Storage Manager server software, Tivoli Storage
Manager client software, the server platform, and the client platform all have at
least minimal monitoring or management capabilities. Often small networks may
have no more than this (that is, no additional network management hardware or
software), with limited or no network administration expertise. This makes the
network a weak link in the overall management of the implementation.
Network design, implementation, and operation are beyond the scope of this
book. However, we cover some basic recommendations.
2.7.1 Network considerations
The network speed to back up clients should be enough to transport common
data and backup data. Generally, the backup should be done during nonworking
hours. We call this period the backup window. While it is possible to split client
backups to minimize network bandwidth, it makes the backup administration
more difficult.