226 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning
The vpathmkdev command creates files vpathMsN in the /dev/dsk/ and /dev/rdsk/ directories
by creating links to the pseudo-vpath devices /devices/pseudo/vpathdd*, which are created by
the SDD driver.
Files vpathMsN in the /dev/dsk/ and /dev/rdsk/ directories provide block and character access
to an application the same way as the cxtydzsn devices created by the system. The
vpathmkdev command is executed automatically during SDD package installation and should
be executed manually to update files vpathMsN after hardware reconfiguration.
The showpath command lists all SDD devices and their underlying disks. An example of the
showpath command is displayed in Example 7-23.
Example 7-23 Sun Solaris showpath command output
Changing an SDD hardware configuration in Sun Solaris
When adding or removing multi-port SCSI devices from a Sun Solaris system, you must
reconfigure SDD to recognize the new devices. Perform the following steps to reconfigure
1. Shut down the system. Type shutdown -i0 -g0 -y and press Enter.
2. Perform a configuration restart. From the OK prompt, type boot -r and press Enter.
This uses the current SDD entries during restart, not the new entries. The restart forces
the new disks to be recognized.
3. Run the SDD configuration utility to make the changes to the directory /opt/IBMdpo/bin.
Type cfgvpath -c and press Enter.
4. Shut down the system. Type shutdown -i6 -g0 -y and press Enter.
5. After the restart, change to the /opt/IBMdpo/bin directory by typing cd /opt/IBMdpo/bin.
6. Type devfsadm and press Enter to reconfigure all the drives.
7. Type vpathmkdev and press Enter to create all the vpath devices.
For specific information about SDD commands, check IBM TotalStorage Multipath Subsystem
Device Driver User’s Guide, SC30-4096.
Note: cfgvpath without the -c option should not be used after hardware reconfiguration,
since the SDD driver is already initialized with the previous configuration information. A
reboot is required to properly initialize the SDD driver with the new hardware configuration
Tip: Note that you can use the output from showvpath to modify iostat or sar information
to report stats based on vpaths instead of hdisks. Gather iostats to a file, and then replace
the disk device names with the corresponding vpaths.