Troubleshooting guide

114 Novell eDirectory 8.8 SP7 Troubleshooting Guide
23.2 Repeated eDirectory Logins
Repeated eDirectory logins can use up the available memory. Disable the Login Update attribute
using iMonitor to overcome this problem.
23.3 Enabling Event System Statistics
Time related statistics are maintained for every event thrown and consumed in eDirectory. This
information is useful for troubleshooting event consumer issues. These statistics are not required for
normal functioning of directory; therefore, they are disabled for performance reasons. Event statistics
can be enabled at runtime by using iMonitor advanced configuration parameters.
To view the event statistics, set the
ENABLE_EVENT_STATISTICS parameter and restart the server. It is
a permanent configuration parameter.
23.4 Tracking Memory Corruption Issues on Linux
On Linux platforms, eDirectory uses Google malloc ( libtcmalloc ) as the default memory allocator.
To track memory corruption issues, set the
MALLOC_CHECK_ environment variable in the ndsd
startup script. The startup script checks for this variable. If set, the default system malloc is used, else
libtcmalloc is loaded.
MALLOC_CHECK Settings in ndsd
 When MALLOC_CHECK_ is set to 0, any detected heap corruption is silently ignored.
 When
MALLOC_CHECK_ is set to 2, abort is called immediately.
This helps to identify the real cause of the memory corruption at early stages, which might be
difficult to track later.
23.5 TCP Connection not Terminating after Abnormal Logout
Sometimes the OES Linux server fails to detect a client host that has gone down abruptly due to a
workstation crashing or a power outage. However, the connection is active for the default timeout
(about 12 to 15 minutes) before the connection is cleared. If you have set the concurrent connections
to 1, it is recommended that you either terminate the connection manually, or wait for the estimated
timeout before logging in again. This situation occurs when the watchdog process fails to close the
connection cleanly. So, if the concurrent connections are set to 1 and the connection is not cleared by
the watchdog, users cannot log in. Linux kernel provides three parameters to change the way
keepalive probes work from the server side. Use these parameters to implement a workaround at
the TCP level.
These parameters are available in
/proc/sys/net/ipv4/ directory.

tcp_keepalive_time : Determines the frequency of sending the TCP keepalive packets to keep
a connection alive if it is currently unused. This value is used only when
keepalive is enabled.
The
tcp_keepalive_time takes an integer value in seconds. The default value is 7200 seconds
or 2 hours. This holds good for most of the hosts and does not require many network resources.
If you set this value to low, it engages your network resources with unnecessary traffic.