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Function : Clusters
NSPingServer - Attempt to detect if a server is reachable.

#include <ns.h>

    char far *pServerName,
    DWORD far *pdwIndex,
    DHANDLE far *phList);
Description :

The NSPingServer function determines if a Lotus Domino Server is reachable. In addition this function optionally retrieves the specified server's workload index (if any), the name of the cluster (if any) to which the server belongs, and a list (of type TEXT_LIST), all members in the server cluster including the specified server. If the server is in a BUSY state, the return status is set to ERR_SERVER_UNAVAILABLE. If the server has been restricted by the system administrator, the return status is set to ERR_SERVER_RESTRICTED. In either state, the server continues to return its availability index and cluster member list if the pdwIndex and phList parameters are not NULL.

If specified as non-NULL on input, the pdwIndex parameter contains the

server's current availability index. This index is a value from 0 - 100. The index value is compared with the SERVER_AVAILABILITY_THRESHOLD value that is set by the server administrator at the console, or in the server notes.ini file. If the availability index falls below the value specified by SERVER_AVAILABILITY_THRESHOLD, then the server enters a BUSY state. In this state, the server does not allow newclient sessions to be established. The server continues to maintain existing client sessions and replication activities when BUSY.

Similar behavior occurs if a server is RESTRICTED. An administrator can place a server in a RESTRICTED state by setting SERVER_RESTRICTED=1 in the server notes.ini file. Servers that do not participate in workload balancing (such as, R3 servers or non-cluster members) always return 0 if this item is requested.
In addition, if the phList parameter is specified as non-Null on input, the name of the cluster to which the server belongs and a complete list of other cluster members is returned if the function is successful and the input server is a member of a Domino cluster. If the list is non-Null on return then the first entry (position 0) contains the name of the cluster to which the server belongs. The remaining entries (if any) contain the names of the server members that are part of the cluster, including the specified input server.
The caller should lock the returned list down using the OSLockObject function before processing the list and unlock it with OSUnLockObject when processing is completed. Use the ListGetNumEntries function to determine the number of entries in the returned list. Use the ListGetText function to retrieve the individual components of the list. The returned list is sorted by workload level, and lists the server with the least workload first.

For more information about managing database availability in a cluster,

TCP/IP port mapping, and workload balancing, see the Domino Administration Help database.

Parameters : Input : pServerName - Address of null-terminated target server name string (required). For partitioned, clustered servers that are accessed through a configured TCP/IP port mapping, the server name must be distinguished and in canonical format. Otherwise, a server access error will be returned. All other server names can be in abbreviated format.

pdwIndex - Address of location to store load index of pServerName (optional). Specify NULL for this argument if you do not wish the server's availability index to be returned.

phList - Address of location to store handle to TEXT_LIST of cluster name followed by one or more names of servers in cluster (optional). Specify NULL for this argument if you do not wish the list to be returned.

Output : (routine) - If server is reachable, NOERROR; If server is busy, ERR_SERVER_UNAVAILABLE; If server is restricted, ERR_SERVER_RESTRICTED; Otherwise, one of a number of possible ERR_xxx errors.

pdwIndex - If non-NULL on input, will contain the load index of the target server (i.e., 0-100 where 100 is the least loaded value). A value of zero and a return status of zero will indicate that the server does not participate in load balancing.

phList - If non-NULL on input, will contain a HANDLE to a TEXT_LIST of cluster name followed by one or more server names which are members of the cluster in which 'pServerName' is participating, if any. Output of NULLHANDLE and a function return status of zero indicates the 'pServerName' is not a member of a cluster. The caller is responsible for freeing the memory associated with the list if this parameter is Non-NULL.

Sample Usage :

#include <ns.h>

   STATUS error = NOERROR;
   DWORD  dwLoadIndex = 0;
   char   *pServerName = "elvis/iris";

   /* Check for load and/or cluster members, if any */

   error = NSPingServer(pServerName, &dwLoadIndex, &hList);    
   if (!error || ERR(error) == ERR_SERVER_UNAVAILABLE)
      printf("Server '%s' load index = %ld.\n", pServerName, dwLoadIndex);

      if (hList == NULLHANDLE)
         printf("Server '%s' is not a member of any cluster.\n",  pServerName);
         char *pBuffer; 
         char Buffer[MAXUSERNAME];
         WORD BufferLength;
         WORD i;
         WORD NumListEntries;
         void far *lpList;

         lpList = OSLock(void, hList);
         NumListEntries = ListGetNumEntries(lpList, FALSE);
         if (NumListEntries > 0)
            /* first entry is the cluster name */
            error = ListGetText(lpList, FALSE, 0, &pBuffer, &BufferLength);
               strncpy(Buffer, pBuffer, BufferLength);
               Buffer[BufferLength] = '\0';

               printf("Server '%s' is a member of the '%s' cluster.\n",
        pServerName, Buffer);

            /* iterate through cluster members and pinging each
       to determine reachability/availability */

            for (i = 1; i < NumListEntries; i++)
               error = ListGetText(lpList, FALSE, i, &pBuffer, &BufferLength);
               if (!error)
                  strncpy(Buffer, pBuffer, BufferLength);
                  Buffer[BufferLength] = '\0';

                  /*ping the cluster member */
                  error = NSPingServer(Buffer, (DWORD *)NULL, (char *)NULL);
                  if (!error)
                     printf("Server '%s' is reachable.\n", Buffer);

                  if (ERR(error) == ERR_SERVER_UNAVAILABLE)
                     printf("Server '%s' is busy.\n", Buffer);

                  if (ERR(error) == ERR_SERVER_RESTRICTED)
                     printf("Server '%s' is restricted.\n", Buffer);


   /* release temporary server text list resources */
   if (hList != NULLHANDLE)

   return error;
See Also : ListGetNumEntries ListGetText NSGetServerClusterMates OSLockObject OSMemFree OSUnlockObject