sidekiq was hang when using NFS as the gitlab-ci's directory

Summary

sidekiq was hang when using NFS as gitlab-ci's base directory.

Steps to reproduce

we use cephfs as gitlab-ci's base directory. we don't know how to reproduce this issue repeatly. but it's shown many times in our production enviornment. we believe that heavy traffic is a condition of reproducing.

What is the current bug behavior?

the sidekiq process was hang.

What is the expected correct behavior?

the sidekiq process run fine

Relevant logs and/or screenshots

we find the hang job is [archive_traces_cron_worker]，it's visiting the file like /mnt/gitlab-data/gitlab-ci/builds/2018_11/18696/466939.log。

Results of GitLab environment info

Expand for output related to GitLab environment info

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:env:info)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:env:info RAILS_ENV=production)

Results of GitLab application Check

Expand for output related to the GitLab application check

(For installations with omnibus-gitlab package run and paste the output of:
sudo gitlab-rake gitlab:check SANITIZE=true)
(For installations from source run and paste the output of:
sudo -u git -H bundle exec rake gitlab:check RAILS_ENV=production SANITIZE=true)
(we will only investigate if the tests are passing)

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)