15.11 DASD and Backup Devices Sharing a Tower
The system architecture does not require that DASD and backup devices be kept separated. Testing in the
IBM Rochester Lab, we had attached one backup device to each tower and all towers had 45 DASD units
in them, when we did the 3580 002 testing. The 3592J has similar characteristics to the 3580 002 but the
3580 003 and 3592E models have greater capacities which create new scenarios. You aren’t physically
limited to putting one backup device in a tower, but for the newest high speed backup devices you can
saturate the bus if you have multiple devices in a tower. You need to look at your total system or
partition configuration in order to determine if it is possible to use multiple high speed devices on the
system and still get the most out of these devices. No matter what you determine is possible we advocate
spreading your backup devices amongst the towers available.
IBM i 6.1 Performance Capabilities Reference - January/April 2008
©
Copyright IBM Corp. 2008
Chapter 15. Save/Restore Performance
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0
50
100
150
200
GB/HR
Save Restore
Operation
5 to 75 DASD Backup Operations
(User Mix Workload) to Ultrium 3 Tape
520 2 way 16GB Memory
5 Dasd
10 Dasd
15 Dasd
20 Dasd
25 Dasd
30 Dasd
35 Dasd
40 Dasd
45 Dasd
50 Dasd
55 Dasd
60 Dasd
75 Dasd
0
100
200
300
400
500
GB/HR
Save Restore
Operation
5 to 75 DASD Backup Operations
(Large File Workload) to Ultrium 3 Tape
520 2 way 16GB Memory
5 Dasd
10 Dasd
15 Dasd
20 Dasd
25 Dasd
30 Dasd
35 Dasd
40 Dasd
45 Dasd
50 Dasd
55 Dasd
60 Dasd
75 Dasd
