Ubuntu docker

We have a physical machine with Ubuntu 14.04 LTS where ran an application called Ubersmith that uses Docker container: https://docs.ubersmith.com/display/UbersmithDocumentation/Ubersmith+and+Docker One of its container has a MySQL Server, and since we wanted to backup the database generating a .sql file to restore on another host if needed, I've installed mysqlclient directly on the OS and I'm using crontab to ran mysqldump twice a day. That is how I do now: 0 1 * * * /usr/bin/mysqldump -h [login to view URL] -u root --password='******' ubersmith > /backup_mysql_cron/[login to view URL] 0 18 * * * /usr/bin/mysqldump -h [login to view URL] -u root --password='*****' ubersmith > /backup_mysql_cron/[login to view URL] - It has worked fine for us until last week, but now, when this cron runs, mysqld start using a big amount of RAM, for example, the server had 16 GB of memory free, and after the dump, it has only 8 GB and this isn't decreasing after the dump process is finished. Because of this cron, the server starts using swap and its applications become too slow and this affects our customers a lot, then we need someone who has a experience with Ubuntu+Docker+MySQL to find a solution to keep running the dump no affecting the server's applications.