Troubleshooting guide

Chapter 2 Troubleshooting Active Network Management Debugging the Load Balancing daemon lhttpd
Advanced Technical Reference Guide 4.1 • June 2000 112
LOGICAL_CACHE_TABLE = dynamic refresh sync expires
LOGICAL_CACHE_TIMEOUT limit LOGICAL_CACHE_SIZE;
2. Save the file and Install the policy.
How to increase the size of the logical cache
The logical_cache is limited to LOGICAL_CACHE_SIZE which is set by default to 1000 entries.
To increase it, edit the table.def and modify the LOGICAL_CACHE_SIZE parameter. For example:
#define LOGICAL_CACHE_SIZE 2000
Debugging the Load Balancing daemon lhttpd
The Load Balancing daemon lhttpd is one of the “Load Balancing Components” described on page 107.
Load Balancing daemon (lhttpd) is the user mode process that handles HTTP requests, when the load
balancing method is set to HTTP. lhttpd listens for and redirects HTTP requests coming for load balancing.
The process is defined in the fwauthd.conf file
10081 in.lhttpd wait 0
You can debug this process by adding an environment variable:
Set FWBHTTPD_DEBUG 1
Debugging the Server-Load Load balancing algorithm
The Load Balancing algorithm is one of the “Load Balancing Components” described on page 107. There are
five available load balancing algorithms: Server Load, Round Trip, Round Robin, Random, and Domain (in the
Domain algorithm (for HTTP only), VPN-1/FireWall-1 chooses the physical server “closest” to the client, based
on domain names).
How the Server Load algorithm works
In the Server Load load balancing algorithm, VPN-1/FireWall-1 determines the load of each physical server.
There must be a load-measuring agent on each physical server. The Load Balancing service on VPN-
1/FireWall-1 does not trigger the load agents at each incoming connection request. The load agent is triggered
every number of incoming requests, then the result is incremented by one up to a limit, then a new measurement
is performed.
About the Load measuring agent
The parameter that affects the load measuring agent
The lbalance_period_wakeup_sec (30) parameter affects the load agent. It is set to 30 seconds by
default.
How often does VPN-1/FireWall-1 perform server load measurement?
Every "lbalance_period_wakeup_sec" seconds the VPN-1/FireWall-1 daemon (fwd) wakes up and
checks whether the kernel used the load values it produced.
fwd does this by looking in table called "logical_server_table"forthekey"0xffffffff", at the
second value after the ";". A 0 (zero) value means that the kernel did use the load values.
• If this value is other than 0 a new load measure is taken.