Table of Contents
Advertisement
Tape drive
Native speed
(MBps)
Sony AIT-3
12
Whether you use Table 2-14 or your own calculations, it is critical when designing
a Tivoli Storage Manager solution to measure the backup and potential restore
workload against the speed of your tape solution. In our earlier example, for
instance, we calculated that we needed to move 86.6 GB/HR to meet SLAs. So
based on the theoretical numbers above, a solution that is capable of that data
movement would take three LTO Gen 1 tape drives.
In addition to calculating backup workload, an architect must also consider
administrative processes and potential restores when deciding how many tape
drives a system needs. Each day, off-site copies of tapes must be made and
reclamation must occur. A potential restore of a large system could also require
multiple drives to meet SLAs.
A detailed discussion of specific I/O protocol speeds is beyond the scope of this
book. However, you should understand the speeds of the drive you choose and
recommendations for system connectivity. As a general rule, most hardware
vendors recommend no more than two to three tape drives per interface card
and, if using Fibre Channel, that tape traffic be separated from disk traffic.
The information in Table 2-15 will be used when sizing tape libraries and then
when defining them to Tivoli Storage Manager.
Table 2-15 Tape drive configuration worksheet
Library model
Number of drives
Drive model
Number of on-site tape volumes
Number of off-site tape volumes
Number of database volumes
Number of scratch tapes
Number of backup set tape volumes
Native capacity
Assumed speed
(GB)
(GB/HR)
100
33
Chapter 2. Implementation planning
Assumed
capacity (GB)
150
Option
IBM System
Storage™ TS3310
Tape Library
2
3580
19
29
6
9
5
51
Advertisement
Table of Contents
