Secure Path v2.0 for Sun Solaris Installation and Reference Guide

2-2 StorageWorks Secure Path Version 2.0 for Sun Solaris
Compaq Confidential – Need to Know Required
Writer: Cyndi Vaccaro Project: StorageWorks Secure Path Version 2.0 for Sun Solaris Comments:
Part Number: AA-RKYDA-TE File Name: c-ch2 Technical Description.doc Last Saved On: 12/21/99 4:52 PM
Solaris
Disk Services
Secure Path
Devices
Host Bus
Adapters
sd0 sd1 sd2
ldLite0
ldLite1 ldLite2
fcaw0
fcaw1
ldLite
Devices
sda
Devices
LUN 0
LUN 1
LUN 2
HSG80
Controllers
mda0 mda1 mda2 mda3
mda4 mda5
Controller 0
Port 1 Port 2
Controller 1
Port 1 Port 2
RAID
Storage
Subsystem
Solaris
Server
SHR-1599
Hub 0 Hub 1
Figure 2-1. Software Components Comprising the Paths to Storage
Secure Path Drivers and spdaemon
The Secure Path (SP) drivers reside between the Solaris sd disk driver and the
Fibre Channel (FC) host bus adapter driver. There are 3 drivers (mda, ldLite
and path) that together along with the spdaemon provide Secure Path’s path
failover functionality. When a path from the server to the storage system is
active, the drivers act as a “pass-through” agent. All I/O from the Solaris sd
driver is sent directly to the FC host bus adapter (HBA) driver.
When an active path fails (due to a cabling problem, for example), the mda
driver stops sending I/O to the HBA driver and signals the Secure Path
spdaemon that a failure event has been detected. The mda driver then activates
the standby path and reissues all pending I/O as well as subsequent I/O to the
newly active path. Once the standby path has successfully been activated, the
driver signals the spdaemon that the failover has completed successfully. The
spdaemon logs the event messages to the console and the system log file, and
sends email notification to the root account on the host (or another specified
user). The Secure Path drivers and the spdaemon are transparent to
applications.