I ignored about this warning. why?
Exadata Database Machine Full Racks and Oracle Exadata Database Machine X2-2 Half Racks have three Sun Datacenter InfiniBand Switch 36 switches. The switch at rack unit 1 (U1) is referred to as the spine switch. The switches at rack unit 20 (U20) and rack unit 24 (U24) in Oracle Exadata Database Machine X2-2 racks, or unit 21(U21) and rack unit 23 (U23) in Oracle Exadata Database Machine X2-8 Full Racks are referred to as leaf switches. The spine switch is the Subnet Manager Master for the InfiniBand subnet. It has priority 8.Sun Datacenter InfiniBand Switch 36 Topic Set
By setting a Subnet Manager to a higher priority than another Subnet Manager, it becomes the primary (or Master) Subnet Manager.Infiniband Switch (01) = spine switch (spine switch is the Subnet Manager Master) - So, It should have a higher priority and Exadata Document (The spine switch is the Subnet Manager Master for the InfiniBand subnet. It has priority 8).
However, I found something wrong, maybe I tested many thing on Exadata.
# getmasterSo, Relocated Subnet Manager Master to another switch. remote to leaf switch (exasw-ib2 ) and then disable/enable SM.
20110530 11:06:00 OpenSM Master on Switch : 0x0021286ccca9a0a0 ports 36 Sun DCS 36 QDR switch exasw-ib2 enhanced port 0 lid 4 lmc 0
# ssh exasw-ib2It's relocated to 01 (Infiniband Switch).
Stopping IB Subnet Manager.. [ OK ]
Starting IB Subnet Manager. [ OK ]
20110530 11:08:31 OpenSM Master on Switch : 0x0021286cd635a0a0 ports 36 Sun DCS 36 QDR switch exasw-ib1 enhanced port 0 lid 1 lmc 0.