Environment
Novell Open Enterprise Server 11 (OES 11) Linux
EMC PowerPath
Situation
One or more NSS pools are not visible in nssmu.
nlvm debug files ( /var/opt/novell/log/nss/debug/ ) show "duplicate pool segment" messages, that suggest a "possible multi-path problem".
Resolution
Edit the NLVM configuration file (/etc/opt/novell/nss/nlvm.conf), and add a statement, or statements to exclude the duplicate devices. The syntax prior to OES11 SP1 IS case sensitive, and does not support wildcard characters. An example follows:
Exclude devices=sda;sdb;sdc;sdd
The syntax after OES11 SP1 IS also case sensitive, but it does support wildcard characters. An example follows:
Exclude devices=sd*
Cause
EMC PowerPath creates a new device name that represents the active path for each LUN presented by an EMC SAN to a server, or group of servers. The new devices are named /dev/emcpowera, /dev/emcpowerb, etc. However, PowerPath does not hide the original device names (/dev/sda, /dev/sdb, /dev/sdc, etc.). These /dev/sd* devices are treated by the server as if they were all unique devices, when in reality, they are just duplicate paths to the same devices presented by PowerPath. Novell Linux Volume Manager (NLVM) gets confused when it sees two devices that have duplicate pools. In reality, they are not duplicate pools, just duplicate paths to the same pool.