UNIX for Dummies Questions & Answers

Hi,guys:
recently,i am puzzled by a question .when i create a new file named by /etc/logrotate.d/debug. The cont. is listed as follow:
/var/log/debug {
rotate 3
missingok
notifempty
size=2k
prerotate
/bin/kill -HUP `cat /var/run/syslogd.pid 2> /dev/null` 2> /dev/null || true
endscript
}
I mean to make the log file which is located /var/log/debug rotate when it's length is over 2048 bytes;however,the file is never rotated by system according to the configuration .Even though, the file length is over 5115 bytes. why,why ,why......
any answer or suggestion is appreciated!!!

thanks in advanced!