Software Manual
Table Of Contents
- Contents
- About this Guide
- NAS Data Path Manager
- Product Overview
- Data Path Concepts
- Install NAS Data Path Manager
- Monitor Data Paths
- Use Performance Monitor to Monitor HBAs
- View Volume Groups for Path Information
- Decide Whether to Manage the Data Paths
- Manage the Data Paths
- Text API Commands for NAS Data Path Manager
- Glossary
- Index
Glossary
38 hp StorageWorks NAS Data Path Manager Installation and User’s Guide
High Availability (HA)
HA systems are designed to avoid a loss of service during both planned and unplanned downtime.
An HA system is based on clusters that have two NAS servers, a Quorum server, and storage that
may come from either a dedicated storage configuration or a SAN. The NAS servers share access
to the storage and provide failover capabilities for each other, but function as independent servers.
Host
The server that acts as a file server running the NAS 8000 software.
Host bus adapter (HBA)
A PCI or PCI-X card used to connect to SCSI or SCSI fibre-channel devices.
Load balancing
An algorithm that distributes data transfer across all preferred paths. The NAS 8000 uses a
least-used algorithm for optimizing performance.
Logical Unit Number (LUN)
A physical or virtual storage device referred to as a logical unit. A logical Unit Number (LUN) is a
value that identifies a specific logical unit with a target ID number.
Non-optimal path
Those data paths between an HBA and a specific LUN, evaluated by Data Path Manager and
determined to be less efficient than others. By default, Data Path Manager will assign non-optimal
paths as alternate paths—used for path failover.
Optimal path
Those data paths between an HBA and a specific LUN, evaluated by Data Path Manager and
determined to more efficient than others. By default, Data Path Manager will assign optimal paths
as preferred paths—used for path load balancing between the HBA and LUN.
Off-line
The state of a path that has been removed from service by failure or by being taken off-line
manually. If a path is taken off-line, it reverts to its previous mode when it is brought back on-line.
Preferred path
Preferred paths are those data paths between an HBA and a specific LUN, evaluated by Data Path
Manager and determined to be optimal paths. Preferred paths are used for path load balancing
between the HBA and LUN.
WWN
The World Wide Name of a device. A WWN is a unique alpha-numeric identifier for hardware.
When Data Path Manager is enabled, each initiator (HBA) and target (controller) is identified by a
world wide name (WWN) in the Volume Groups table.