Choosing the Right Disk Technology in a High Availability Environment DRAFT Version 2.0, August 1996

DRAFT -- Revision 2.0
August 22, 1996Page 3
Disk Link Technology ............................................ 38
Number of Targets on a Disk Link .................................. 38
Performance benchmarks ........................................ 40
Summary of performance of various disk technologies .................. 40
HIGH AVAILABILITY (HA) DISK CONSIDERATIONS ........................ 41
DECISION CRITERIA ................................................. 42
The need for on-line failed disk replacement versus scheduling downtime
....................................................... 43
The need for data redundancy ..................................... 43
The need for double data redundancy ............................... 44
The need for continuous data redundancy ........................... 44
Purchase cost ................................................. 45
Footprint ...................................................... 45
Performance .................................................. 48
Backup strategy ................................................ 48
Total capacity requirements ....................................... 49
Power source redundancy ........................................ 50
Total distance among computer systems ............................ 50
DISK SELECTION MATRIX ............................................ 50
SUMMARY ......................................................... 54