Why does crontab run twice while I set once everyday?

Question

I used CentOS for Wordpress web server. I want backup media and SQL once per day, so I edit crontab as below:

[john@cent ~]$ crontab -e
TZ=Asia/Ho_Chi_Minh
15 3 * * * /bin/sh /home/john/deploy/job/backup-mysql.sh 2>&1 >> /home/john/deploy/job/log/backup-mysql.log
30 3 * * * /bin/sh /home/john/deploy/job/backup-media.sh 2>&1 >> /home/john/deploy/job/log/backup-media.log

I mean run these job once per day, but it really run twice:

[john@cent ~]$ cd deploy/mediadump/
[john@cent mediadump]$ ls
07-08-2015_03.30.01.uploads.tar.gz
07-08-2015_14.38.01.uploads.tar.gz
08-08-2015_03.30.01.uploads.tar.gz
08-08-2015_14.38.01.uploads.tar.gz
09-08-2015_03.30.01.uploads.tar.gz
09-08-2015_14.38.01.uploads.tar.gz

What did I wrong?

UPDATE The sqldump job run same with mediadump. I listed files, as @lain and @Paul suggested, check log file again, and I realize the root user run jobs at 14:38 for media and 14:36 for sql:

[root@cent datadump]# ls -l
-rw-r--r-- 1 john john 2391638 Th08  7 03:15 07-08-2015_03.15.01.sql
-rw-r--r-- 1 root  root  2437070 Th08  7 14:36 07-08-2015_14.36.01.sql
-rw-r--r-- 1 john john 2560015 Th08  8 03:15 08-08-2015_03.15.01.sql
-rw-r--r-- 1 root  root  2667435 Th08  8 14:36 08-08-2015_14.36.01.sql
-rw-r--r-- 1 john john 2618756 Th08  9 03:15 09-08-2015_03.15.01.sql
-rw-r--r-- 1 root  root  2928775 Th08  9 14:36 09-08-2015_14.36.01.sql

Ago, I tested crontab on root user by the way edit /etc/crontab. I forgot clear that file before switch to John for run needed job. I fix it ok. Thanks a lot @lain, @Paul Haldane.

Answer 1

It seems that you are running the same job as two different users. The log files should have been able to help you track that down. The timestamps on the dump files confirm multiple users.