A cluster 2005 with 4 nodes failover with this error :
SQL Server has encountered 1 occurrence(s) of I/O requests taking longer than 15 seconds to complete on file [g:\Log\distribution.LDF] in database [distribution] (17). The OS file handle is 0x0000000000000A94. The offset of the latest long I/O is: 0x00000028b3be00
before in the agent log, we can find :
Date 10/06/2010 00:01:29
Log SQL Agent (Current - 10/06/2010 01:05:00)
 SQLServer Error: 65535, SQL Network Interfaces: Error Locating Server/Instance Specified [xFFFFFFFF]. [SQLSTATE 08001]
I search to explain this incident.