Answer: This can occur normally when the target database is running on the secondary (mirror) server in a High Availability (HA) setup and failover occurs; for example:

• Foxhound is successfully connected to the secondary (mirror) server, and the Foxhound ping process is successful.

• Foxhound displays this in the "database disposition" field...

  Read-only secondary (mirror) database. Arbiter was connected. Partner was connected, synchronized. 
  

• The primary server fails, and the secondary (mirror) server automatically becomes the primary server as part of the failover process.

• Foxhound now displays this in the "database disposition" field...

  Updatable primary database. Arbiter is connected. Partner is disconnected, synchronizing.
  

• Foxhound remains connected to the server which used to be the secondary (mirror) server and now is the primary server.

  This may be "curious" behavior on the part of SQL Anywhere but it is expected.

• Foxhound continues to gather samples, but the ping process fails because it cannot establish a new connection to a server that doesn't exist.

Machine: XPS ... Server: partner2_demo ... Database: demo ... Updatable primary database. Arbiter was connected. Partner was disconnected, synchronizing. Response... Heartbeat, Samples Interval Sample, Ping 3:23:11 PM 10s 3ms / 76ms / Failed ... Ping failed at 3:23:12 PM: SQLCODE -100, SQLSTATE 08W01, Database server not found connection_string = "SERVER=secondary_demo;UID=dba;HOST=Computer1:55501,Computer2:55502;AutoStop=NO;AutoStart=NO;ConnectionName=Foxhound-ping-7396;CPOOL=NO" ping_id = 968870, sampling_id = 119, started_at_sample_set_number = 968867, return_code = -100, diagnostic_code = 1

If you stop and restart sampling to force Foxhound to reconnect to the secondary (mirror) database, that will now fail...

Response... Heartbeat, Samples Interval Sample, Ping 3:31:23 PM 8.9s -- Database server not found -- 3:31:14 PM 8.2s -- Database server not found at -- 3:31:06 PM 89ms -- Sampling stopped -- 3:31:06 PM 9.9s -- Sampling stopped at -- 3:30:56 PM 9.9s 1ms / 34ms / Failed ...