HP StorageWorks Command Console V2.5 User Guide (AA-RV1UA-TE, March 2005)
Table Of Contents
- Contents
- About this Guide
- About SWCC
- Using Command Console
- Setting Up Notification
- Required Components for Notification
- Setting Up Pager Notification
- Using SWCC with a Third-Party Storage Management Program
- Using Event Logging on the Client System to Monitor Your Subsystem
- Interpreting Agent Email Messages
- About Event Information Fields
- Mapping State Change Digits to RAID System Components
- Table 11: State Change Digit Position and Corresponding RAID system Component
- The First Digit of the State Change Field (Overall RAID System)
- The Second Digit of the State Change Field (Disks)
- The Third Digit of the State Change Field (Power Supply)
- The Fourth Digit of the State Change Field (Fans)
- The Fifth Digit of the State Change Field (Battery)
- The Sixth Digit of the State Change Field (Temperature)
- The Seventh Digit of the State Change Field (This_Controller)
- The Eighth Digit of the State Change Field (Communications LUN)
- The Ninth Digit of the State Change Field (Other_Controller)
- The 10th Digit of the State Change Field (External Factors)
- The 11th Digit of the State Change Field (Logical Units)
- Using the Storage Window
- Why Use the Storage Window?
- Configuring a Controller
- Creating Virtual Disks
- Deleting Virtual Disks
- Modifying Virtual Disks
- Configuring the Operating System to Recognize Virtual Disk Changes
- Setting Passwords and Security Options (Network Only)
- Managing and Creating Spare Devices
- Using Configuration Files
- Understanding the Icons
- CLI Window
- Integrating SWCC with Insight Manager
- Troubleshooting
- Troubleshooting Connection Problems
- Invalid Network Port Numbers During Installation
- Network Port Assignments for UNIX-Client/Server Systems
- DHCP and WINS
- Connecting Via the Host SCSI Port
- “Access Denied” Message
- Adding New System by Using Internet Protocol Address May Cause Client to Stop Responding
- “No Agent Running” Message When Adding System to the Navigation Tree
- Troubleshooting the Client
- Authorization Error When Adding an Agent System
- Cannot Open Storage Window
- Client Hangs When LUN Is Deleted
- CLI RUN Commands
- Event Notification for Subsystems Connected to a Client System
- Invalid or Missing Fault Displays and Event Logs
- Pager Notification Continues After Exiting the Command Console Client
- Reconfiguration After Controller Replacement
- Some Graphics Do Not Scale Well with Large Fonts
- Starting Client from the Command Prompt
- Warning Message Windows
- Virtual Disk Recovery from a Configuration File
- Troubleshooting the HS-Series Agents
- Cluster Integration for the HS-Series Agents
- Troubleshooting Connection Problems
- Using the Command Console LUN
- Interpreting SNMP Traps
- Glossary
- Index
Glossary
138 Command Console V2.5 User Guide
RAID 5 RAID 5 virtual disks use parity for data redundancy. A RAID 5
virtual disk is a type of striped parity virtual disk.
In a RAID 5 virtual disk, host data is written in its entirety as a
strip representing one I/O request into a much larger stripe of
I/O requests stored across the virtual disk membership. An
additional strip for parity information is written into each stripe.
This technique offers the same read performance as reading
from a single device. However, in a RAID 5 virtual disk,
multiple read I/O requests can occur resulting in a very high
overall subsystem read performance.
Write performance, however, is much worse. Because writing a
small strip of data into a larger amount of data on a device is
really a read-modify-write operation, writing becomes
time-consuming. In addition, because each data stripe is
protected by parity information, there is a significant level of
data redundancy for high availability.
RAID 5 virtual disks provide high read performance and high
availability at reasonable cost. They are optimal for use in
applications that have relatively high I/O read request rates and
require relatively low data transfer rates.
read cache A block of high-speed memory used to buffer data being read
from storage devices by a host. A read cache responds to host
read requests from local cache memory if possible rather than
from external storage devices. Therefore, it increases the
controller's effective device access speed.
The controller maintains copies of data recently requested by
the host in cache, and it may fetch blocks of data ahead of a
request in anticipation that the controller will access the next
sequential blocks. In a typical read cache, host write requests
are handled without involving caching.