# Ansible fork and serial relationship? **URL:** \ **Category:** Ansible Project\ **Created:** [February 22, 2019, 2:54am UTC](https://forum.ansible.com/t/ansible-fork-and-serial-relationship/29739 "2019-02-22T02:54:50Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![leerin](https://avatars.discourse-cdn.com/v4/letter/l/e19b73/32.png) [@leerin](https://forum.ansible.com/u/leerin)\ **Post date:** [February 22, 2019, 2:54am UTC](https://forum.ansible.com/t/ansible-fork-and-serial-relationship/29739/1 "2019-02-22T02:54:50Z")
Hi experts, I found one interesting thing about ansible fork and serial. But don’t know what is the exact relationship between these two values. Following is the result of my testing: 21 VMs 1. fork=10, serial=100%, ansible will fail with some hosts unreachable randomly. 2. fork=15/25, serial=100%, ansible will success. 3. fork=10, serial=10. ansible will success. Te conclusion: seems the serial shall be less than fork, or can’t be much larger than fork. Question: 1. the randomly unreachable failure is a ansible bug? I foud one issue report: [https://github.com/ansible/ansible/issues/18188](https://github.com/ansible/ansible/issues/18188) 2. Is there any suggestion about the fork and serial value setting? I don’t find any document about this. Thanks, Ruby