Many a time, we observe that it takes too much time to login into the server. Most of the time the reason being, the wtmpx file is growing, filling up the /var partition (often part of the root partition). In extreme cases, it may even prevent the possibility of logging in, because utmpx entries cannot be made, and login asks the user to exec login from the lowest level shell. In such cases /var/adm/wtmpx needs to be truncated without causing problems.
Using logadm command
The most appropriate way to limit the size of /var/adm/wtmpx is using logadm. For example, to limit the size of logfile to 300MB and rotate the logfile if its greater than 300MB :
# logadm -C 4 -c -s 300m -w /var/adm/wtmpx
-C count Delete the oldest versions until there are not more than count files left. -p period Rotate a log file after the specified time period (period) . -c Rotate the log file by copying it and truncating the original logfile to zero length, rather than renaming the file. -w entryname Write an entry into the config file (that is, /etc/logadm.conf) -s size Rotate the log file only if its size is greater than or equal to size. -z count Compress old log files after all other commands have been executed.
As the -w option is used, we would also get an entry in the /etc/logadm.conf file as :
# tail -1 /etc/logadm.conf wtmpx -C 4 -c -s 300m /var/adm/wtmpx
To run the rule we just created using logadm, use the -v option which will print the output in verbose mode.
# logadm -v --lines omitted-- # processing logname: /var/adm/wtmpx # using default template: $file.$n mkdir -p /var/adm # verify directory exists # cp -fp /var/adm/wtmpx /var/adm/wtmpx.0 # rotate log file via copy (-c flag) # cp -f /dev/null /var/adm/wtmpx # trucate log file (-c flag) touch /var/adm/wtmpx chown 4:4 /var/adm/wtmpx chmod 644 /var/adm/wtmpx # recording rotation date Tue Feb 25 13:51:14 2014 for /var/adm/wtmpx # writing changes to /var/logadm.conf
Verify the results :
# ls -l /var/adm/wtmpx* -rw-r--r-- 1 adm adm 0 Dec 25 13:51 /var/adm/wtmpx -rw-r--r-- 1 adm adm 362328000 Dec 25 12:54 /var/adm/wtmpx.0
zero-out the file
Another easiest way to trancate the wtmpx file is to zeo it out as :
# > /var/adm/wtmpx