Can anybody tell me what elapsed status  means in system timer?I use this configure for xxx.timer:# /usr/lib/systemd/system/tianji.timer[Unit]Description=check sm and sms every min[Timer]OnBootSec=1minOnUnitActiveSec=1minUnit=tianji.service[Install]WantedBy=multi-user.targetWhen I reboot , sometimes but not always tianji.timer will go to elapsed status , and tianji.service will never been actived !!Only when I manully restart tianji.timer or tianji.service ,next will be ok.#systemctl status   tianji.timer tianji.timer - check sm and sms every min   Loaded: loaded (/usr/lib/systemd/system/tianji.timer; enabled; vendor preset: disabled)   Active: active (elapsed) since Thu 2017-08-10 11:32:43 CST; 6 days agoAug 10 11:32:43 localhost.domain systemd[1]: Started check sm and sms every min.Aug 10 11:32:43 localhost.domain systemd[1]: Starting check sm and sms every min.#systemctl restart   tianji.timer#systemctl status   tianji.timer tianji.timer - check sm and sms every min   Loaded: loaded (/usr/lib/systemd/system/tianji.timer; enabled; vendor preset: disabled)   Active: active (waiting) since Wed 2017-08-16 13:06:57 CST; 1s agoAug 16 13:06:57 localhost.domain systemd[1]: Stopping check sm and sms every min.Aug 16 13:06:57 localhost.domain systemd[1]: Started check sm and sms every min.Aug 16 13:06:57 localhost.domain systemd[1]: Starting check sm and sms every min.After my test I find this issue is same to this problem I already know that when delete option:OnBootSec=1min  and then reboot , xxx.timer status will go to elapsed status , but my configure is using OnBootSec=1min and have probability to reproduction 
Why systemd timer goto elapsed status and service never actived?
systemd