Computer Associates ARB6002700WF0. ..... Administration Guide - Page 44

Defining Data-transfer Requirements Device type Approximate Transfer rate 2:1 (compressed data) Mammoth-2 24.0 MB/seconds=86.4 GB/hour Ultrium (LTO) 30.0 MB/seconds=108.0 GB/hour IBM 9890 20.0 MB/seconds=72.0 GB/hour IBM 3590E 15.0 MB/seconds=54.0 GB/hour Maximum Capacity (compressed data) 160 GB 200 GB 40 GB 60 GB Even though a single device may not be able to give the data transfer rate of 200 GB per hour set by our example, using multiple media devices should be able to achieve this aggregate transfer rate. For example, if you are using Ultrium tape drives, you need 2 tape drives to achieve 200 GB per hour, or 5 DLT 8000 drives to achieve the same throughput. How Much Network Bandwidth Do You Have? Now you need to consider your network. More than any other factor, your available network bandwidth determines the amount of data that you can realistically transfer during a backup period. The following table compares the performance of different types of networks. As you can see, network performance can significantly impede large backup operations. Network Type Theoretical Transfer Rate Realistic Realistic Transfer Rate* Throughput 10Base-T Ethernet 10 mbps =1.25 MB/seconds 40-50% 500 KB/seconds=1.8 GB/hour 100Base-T Ethernet 100 mbps=12.5 80% MB/seconds 10 MB/seconds=36 GB/hour 1 Gigabit Ethernet 1000 mbps=125 70% MB/seconds 87.5 MB/seconds=315 GB/hour *If you are backing up concurrently with other operations, remember that your backup operations will not achieve the maximum, realistic transfer rate listed. 2-6 Administrator Guide