EMC 300-000-978 REV A03 User Manual

Device Naming

When the host on the R2 side boots, it is connected to a different 
Symmetrix system and set of volume IDs. Therefore, the 

emcp.conf

 

and 

powermt.custom

 files (which are identical to the R1 files since 

the boot disk is identical) are modified to create a valid mapping 
between the emcpower device and native path device for both R1

 

and 

R2 locations. Having both the R1

 

and R2 Symmetrix volume IDs in 

the 

emcp.conf

 file ensures a valid mapping between the pseudo 

devices and the underlying native path device. PowerPath will 
determine which Symmetrix volume IDs are valid (that is, the visible 
ones) and will act accordingly when either the R1or the R2 host

 

is 

booted.

PowerPath for Solaris presents PowerPath-enabled storage system 
logical devices to the operating system by all their native devices plus 
a single PowerPath-specific pseudo device. Applications and 
operating system services can use any of these devices—native or 
pseudo—to access a PowerPath-enabled storage system logical 
device.

A native device describes a device special file of one of the following 
forms:

◆

Block device—

/dev/dsk/c

t

d

s

◆

Raw device—

/dev/rdsk/c

t

d

s

where:

◆

The 

c

 # is the instance number for the interface card.

◆

The 

t

 # is the target address of the storage system logical device 

on the bus.

◆

The 

d

 # is the storage system logical device at the target.

◆

The 

s

 # is the slice, ranging from 0 to 7.