Computer Associates BABWBR1151S38 Implementation Guide - Page 19

Data Transfer Requirements SCSI or Fibre Interface Considerations No device is faster than its connection to its data source. Current backup devices connect using standard SCSI or fibre interfaces. The following table lists the common varieties. Version Bus Width Approximate Maximum Data-transfer Rate Wide Ultra SCSI Ultra2 SCSI Wide Ultra2 SCSI Ultra 160 SCSI Ultra 320 SCSI Fibre Channel Fibre Channel 16 bits 8 bits 16 bits 16 bits 16 bits 1 Gb 2 Gb 40 MB/seconds=144 GB/hour 40 MB/seconds=144 GB/hour 80 MB/seconds=288 GB/hour 160 MB/seconds=576 GB/hour 320 MB/seconds=1152 GB/hour 100 MB/seconds=360 GB/hour 200 MB/seconds=720 GB/hour You can see that many of the SCSI interfaces and fibre interfaces will be able to handle your requirement of 200 GB per hour. For example, if you are using a Wide Ultra2 SCSI you can achieve 200 GB in less than an hour. Even if you are using a slower SCSI controller you can use multiple SCSI controllers to achieve the aggregate data transfer rate of 200 GB per hour. Obviously, the SCSI bus or fibre interface should seldom limit your ability to achieve your required data transfer rate. Any of these SCSI varieties could easily meet the 40 GB per hour requirement in our example. Indeed, most could handle the whole 200 GB job in under two hours. A Wide Ultra 160 SCSI could do it in about 30 minutes. Tape Drive Considerations There are many kinds of devices. A few of the most common are listed in the following table. Device type DDS-4 AIT-2 Approximate Transfer rate 2:1 Maximum Capacity (compressed (compressed data) data) 6.0 MB/seconds=21.6 GB/hour 40 GB 12.0 MB/seconds=43.2 GB/hour 100 GB Chapter 2: Planning Storage Environments 19