List of advisors

Advisors are agents within Load Balancer. Their purpose is to assess the health and loading of server machines. This list of advisors are already provided with Load Balancer, but you can also write a custom advisor to suit specific needs.

Table 1. List of advisors
Advisor Name Description
caching proxy The caching proxy advisor opens a connection, sends a caching proxy specific HTTP GET request, and interprets the response as a caching proxy load.
Important: When using the Caching Proxy advisor, Caching Proxy needs to be running on all servers being load balanced. The machine on which the Load Balancer resides does not need to have Caching Proxy installed unless it is collocated on the same machine it is load balancing.
connect The connect advisor does not exchange any protocol-specific data with the server. It simply measures the time it takes to open and close a TCP connection with the server. This advisor is useful for server applications which use TCP, but with a higher-level protocol for which an IBM-supplied or custom advisor is not available.
Custom advisors Dispatcher provides the ability for a customer to write a custom (customizable) advisor. This enables support for proprietary protocols (on top of TCP) for which IBM has not developed a specific advisor. For more information, see Creating a custom advisor.
db2 The DB2 advisor works in conjunction with the DB2 servers. Dispatcher has the built in capability of checking the health of DB2 servers without the need for customers to write their own custom advisors. The DB2 advisor communicates with the DB2 connection port only, not the Java connection port.
dns The DNS advisor opens a connection, sends a pointer query for DNS, waits for a response, closes the connection and returns the elapsed time as a load.
ftp The FTP advisor opens a connection, sends a SYST request, waits for a response, closes the connection, and returns the elapsed time as a load.
http The HTTP advisor opens a connection, sends a HEAD request by default, waits for a response connection, and returns the elapsed time as a load. See Getting service-specific advice with the advisor request or response optionfor more information on how to change the type of request sent by the HTTP advisor.
https The HTTPS advisor is a ″heavyweight″ advisor for SSL connections. It performs a full SSL socket connection with the server. The HTTPS advisor opens an SSL connection, sends an HTTPS request, waits for a response, closes the connnection, and returns the elapsed time as a load. (See also the SSL advisor, which is a ″lightweight″ advisor for SSL connections.)
Note: The HTTPS advisor has no dependency upon server key or certificate content, but they must not be expired.
imap The IMAP advisor opens a connection, waits for an initial message from the server, sends a quit command, closes the connection, and returns the elapsed time as a load.
ldap The LDAP advisor opens a connection, sends an anonymous BIND request, waits for a response, closes the connection, and returns the elapsed time as a load.
ldapuri
New feature New feature:
The LDAP URI advisor allows you better gauge LDAP availability by processing a complete request to the LDAP server.
The advisor:
  1. Opens a connection.
  2. Sends a BIND request, which is based on the advisorrequest field that you define on the server object.
  3. Waits for a response.
  4. Closes the connection.
  5. Returns the elapsed time as a load.
Read Configuring the LDAP URI advisor for more information on configuring this advisor.
newfeat
nntp The NNTP advisor opens a connection, waits for an initial message from the server, sends a quit command, closes the connection, and returns the elapsed time as a load.
ping The ping advisor does not open a TCP connection with the servers, but instead reports whether the server responds to a ping. While the ping advisor may be used on any port, it is also designed for configurations using the wildcard port, over which multiple protocol traffic may be flowing. It is also useful for configurations using non-TCP protocols with their servers.
pop3 The POP3 advisor opens a connection, waits for an initial message from the server, sends a quit command, closes the connection, and returns the elapsed time as a load.
reach The reach advisor pings its target machines. This advisor is also designed for the Dispatcher's high availability components to determine reachability of its reach targets. Its results flow to high availability component and do not appear in the manager report. Unlike the other advisors, the reach advisor starts automatically by the manager function of the Dispatcher component.
sip The SIP advisor opens a connection, sends an OPTIONS request, waits for a response, closes the connection, and returns the elapsed time as a load. The SIP advisor that is supported runs on TCP only and requires an application to be installed on a server that responds to an OPTIONS request.
smtp The SMTP advisor opens a connection, waits for an initial message from the server, sends a quit, closes the connection, and returns the elapsed time as a load.
ssl The SSL advisor is a ″lightweight″ advisor for SSL connections. It does not establish a full SSL socket connection with the server. The SSL advisor opens a connection, sends an SSL CLIENT_HELLO request, waits for a response, closes the connection, and returns the elapsed time as a load. (See also the HTTPS advisor, which is a ″heavyweight″ advisor for SSL connections.)
Note: Be aware of the following:
  • The SSL advisor has no dependency upon key management or certificates.
  • You might want to use the TLS advisor if you find that the SSL advisor is marking servers down, you know that the server is still up, and you see messages stating "No ciphers found."
ssl2http The ssl2http advisor starts and advises on the servers listed under port 443, but the advisor will open a socket to the “mapport″ for HTTP requests. Only use the ssl2http advisor for CBR if the client-to-proxy protocol list is SSL and the proxy-to-server protocol is HTTP.
telnet The Telnet advisor opens a connection, waits for an initial message from the server, closes the connection, and returns the elapsed time as a load.
tls Transport Layer Security (TLS) is the successor to the SSL protocol. TLS 1.0 was the follow up to SSLv3.

You might want to use the TLS advisor if you find that the SSL advisor is marking servers down, you know that the server is still up, and you see messages stating "No ciphers found."

was The WAS (WebSphere Application Server) advisor works in conjunction with the WebSphere Application servers. Customizable sample files for this advisor are provided in the installation directory. For more information, see Example: Implementing the WAS advisor.
wlm The WLM (Workload Manager) advisor is designed to work in conjunction with servers on OS/390 mainframes running the MVS™ Workload Manager (WLM) component. For more information, see The Workload Management Advisor.
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Last updated: April 16, 2014 11:59 AM EDT
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