Contents ●8
Understanding Adaptec Storage Manager
Features.............................................................................................................. 45
Overview............................................................................................................ 45
Physical Devices View................................................................................. 46
Logical Devices View ..................................................................................46
Changing How Drives are Displayed............................................................... 46
Collapsed and Expanded Views .......................................................................47
Component Views.............................................................................................48
Solving Problems
Troubleshooting Checklist ............................................................................... 50
Recovering from a Disk Drive Failure .............................................................50
Failed Disk Drive Protected by a Hot Spare.............................................. 50
Failed Disk Drive Not Protected by a Hot Spare....................................... 51
Failure in Multiple Arrays Simultaneously................................................51
Disk Drive Failure in a RAID 0 Array........................................................ 51
Multiple Failures in the Same Array.......................................................... 51
Introduction to SAS
Terminology Used in This Chapter .................................................................53
What is SAS?...................................................................................................... 53
How Do SAS Devices Communicate?.............................................................. 53
What’s a Phy? ....................................................................................................54
What’s a SAS Port?............................................................................................ 54
What’s a SAS Address?...................................................................................... 55
What’s a SAS Connector? .................................................................................55
What do SAS Cables Look Like?.......................................................................55
How are Disk Drives Identified in SAS? ..........................................................55
What are the SAS Connection Options?.......................................................... 55
Direct-attach Connections......................................................................... 56
Backplane Connections.............................................................................. 56
SAS Expander Connections........................................................................ 56
How is SAS Different from Parallel SCSI?....................................................... 57
Understanding RAID
RAID Technology Overview.............................................................................59
Understanding Drive Segments .................................................................59
Stripe-unit Size............................................................................................ 59
Selecting a RAID Level and Tuning Performance.....................................59
RAID 0 (Non-RAID Arrays) ............................................................................60
RAID 1 Arrays................................................................................................... 61
RAID 10 Arrays................................................................................................. 61