After deploying this onto our Phabricator cluster, I haven't seen any "unable to update local ref" exceptions in 24 hours.
```name="grep --no-filename --before-context=10 'cannot lock ref' /var/log/phabricator/daemons.log | grep 'EXCEPTION: (CommandException)' | awk '{print $1}' | tr --delete '[' | uniq --count"
1 2017-07-19
11 2017-07-20
9 2017-07-21
1 2017-07-23
8 2017-07-24
```