diff --git a/app/views/admin/application_settings/_repository_check.html.haml b/app/views/admin/application_settings/_repository_check.html.haml
index f33769b23c2..fe335f30a62 100644
--- a/app/views/admin/application_settings/_repository_check.html.haml
+++ b/app/views/admin/application_settings/_repository_check.html.haml
@@ -12,7 +12,7 @@
               Enable Repository Checks
             .help-block
               GitLab will periodically run
-              %a{ href: 'https://www.kernel.org/pub/software/scm/git/docs/git-fsck.html', target: 'blank' } 'git fsck'
+              %a{ href: 'https://git-scm.com/docs/git-fsck', target: 'blank' } 'git fsck'
               in all project and wiki repositories to look for silent disk corruption issues.
       .form-group
         .col-sm-offset-2.col-sm-10
diff --git a/app/workers/admin_email_worker.rb b/app/workers/admin_email_worker.rb
index bec0a003a1c..044e470141e 100644
--- a/app/workers/admin_email_worker.rb
+++ b/app/workers/admin_email_worker.rb
@@ -3,6 +3,12 @@ class AdminEmailWorker
   include CronjobQueue
 
   def perform
+    send_repository_check_mail if Gitlab::CurrentSettings.repository_checks_enabled
+  end
+
+  private
+
+  def send_repository_check_mail
     repository_check_failed_count = Project.where(last_repository_check_failed: true).count
     return if repository_check_failed_count.zero?
 
diff --git a/app/workers/repository_check/batch_worker.rb b/app/workers/repository_check/batch_worker.rb
index 76688cf51c1..72f0a9b0619 100644
--- a/app/workers/repository_check/batch_worker.rb
+++ b/app/workers/repository_check/batch_worker.rb
@@ -4,8 +4,11 @@ module RepositoryCheck
     include CronjobQueue
 
     RUN_TIME = 3600
+    BATCH_SIZE = 10_000
 
     def perform
+      return unless Gitlab::CurrentSettings.repository_checks_enabled
+
       start = Time.now
 
       # This loop will break after a little more than one hour ('a little
@@ -15,7 +18,6 @@ module RepositoryCheck
       # check, only one (or two) will be checked at a time.
       project_ids.each do |project_id|
         break if Time.now - start >= RUN_TIME
-        break unless current_settings.repository_checks_enabled
 
         next unless try_obtain_lease(project_id)
 
@@ -31,12 +33,20 @@ module RepositoryCheck
     # getting ID's from Postgres is not terribly slow, and because no user
     # has to sit and wait for this query to finish.
     def project_ids
-      limit = 10_000
-      never_checked_projects = Project.where('last_repository_check_at IS NULL AND created_at < ?', 24.hours.ago)
-        .limit(limit).pluck(:id)
-      old_check_projects = Project.where('last_repository_check_at < ?', 1.month.ago)
-        .reorder('last_repository_check_at ASC').limit(limit).pluck(:id)
-      never_checked_projects + old_check_projects
+      never_checked_project_ids(BATCH_SIZE) + old_checked_project_ids(BATCH_SIZE)
+    end
+
+    def never_checked_project_ids(batch_size)
+      Project.where(last_repository_check_at: nil)
+        .where('created_at < ?', 24.hours.ago)
+        .limit(batch_size).pluck(:id)
+    end
+
+    def old_checked_project_ids(batch_size)
+      Project.where.not(last_repository_check_at: nil)
+        .where('last_repository_check_at < ?', 1.month.ago)
+        .reorder(last_repository_check_at: :asc)
+        .limit(batch_size).pluck(:id)
     end
 
     def try_obtain_lease(id)
@@ -47,16 +57,5 @@ module RepositoryCheck
         timeout: 24.hours
       ).try_obtain
     end
-
-    def current_settings
-      # No caching of the settings! If we cache them and an admin disables
-      # this feature, an active RepositoryCheckWorker would keep going for up
-      # to 1 hour after the feature was disabled.
-      if Rails.env.test?
-        Gitlab::CurrentSettings.fake_application_settings
-      else
-        ApplicationSetting.current
-      end
-    end
   end
 end
diff --git a/app/workers/repository_check/single_repository_worker.rb b/app/workers/repository_check/single_repository_worker.rb
index 116bc185b38..3cffb8b14e4 100644
--- a/app/workers/repository_check/single_repository_worker.rb
+++ b/app/workers/repository_check/single_repository_worker.rb
@@ -5,27 +5,34 @@ module RepositoryCheck
 
     def perform(project_id)
       project = Project.find(project_id)
-      project.update_columns(
-        last_repository_check_failed: !check(project),
-        last_repository_check_at: Time.now
-      )
+      healthy = project_healthy?(project)
+
+      update_repository_check_status(project, healthy)
     end
 
     private
 
-    def check(project)
-      if has_pushes?(project) && !git_fsck(project.repository)
-        false
-      elsif project.wiki_enabled?
-        # Historically some projects never had their wiki repos initialized;
-        # this happens on project creation now. Let's initialize an empty repo
-        # if it is not already there.
-        project.create_wiki
+    def update_repository_check_status(project, healthy)
+      project.update_columns(
+        last_repository_check_failed: !healthy,
+        last_repository_check_at: Time.now
+      )
+    end
 
-        git_fsck(project.wiki.repository)
-      else
-        true
-      end
+    def project_healthy?(project)
+      repo_healthy?(project) && wiki_repo_healthy?(project)
+    end
+
+    def repo_healthy?(project)
+      return true unless has_changes?(project)
+
+      git_fsck(project.repository)
+    end
+
+    def wiki_repo_healthy?(project)
+      return true unless has_wiki_changes?(project)
+
+      git_fsck(project.wiki.repository)
     end
 
     def git_fsck(repository)
@@ -39,8 +46,19 @@ module RepositoryCheck
       false
     end
 
-    def has_pushes?(project)
+    def has_changes?(project)
       Project.with_push.exists?(project.id)
     end
+
+    def has_wiki_changes?(project)
+      return false unless project.wiki_enabled?
+
+      # Historically some projects never had their wiki repos initialized;
+      # this happens on project creation now. Let's initialize an empty repo
+      # if it is not already there.
+      return false unless project.create_wiki
+
+      has_changes?(project)
+    end
   end
 end
diff --git a/changelogs/unreleased/tc-repo-verify-mails.yml b/changelogs/unreleased/tc-repo-verify-mails.yml
new file mode 100644
index 00000000000..b4d3c4b1596
--- /dev/null
+++ b/changelogs/unreleased/tc-repo-verify-mails.yml
@@ -0,0 +1,5 @@
+---
+title: Small improvements to repository checks
+merge_request: 18484
+author:
+type: changed
diff --git a/doc/administration/repository_checks.md b/doc/administration/repository_checks.md
index ee37ea49874..efeec9db517 100644
--- a/doc/administration/repository_checks.md
+++ b/doc/administration/repository_checks.md
@@ -13,12 +13,12 @@ checks failed you can see their output on the admin log page under
 
 ## Periodic checks
 
-When enabled, GitLab periodically runs a repository check on all project 
-repositories and wiki repositories in order to detect data corruption problems. 
+When enabled, GitLab periodically runs a repository check on all project
+repositories and wiki repositories in order to detect data corruption.
 A project will be checked no more than once per month. If any projects
 fail their repository checks all GitLab administrators will receive an email
-notification of the situation. This notification is sent out once a week on
-Sunday, by default. 
+notification of the situation. This notification is sent out once a week,
+by default, midnight at the start of Sunday.
 
 ## Disabling periodic checks
 
@@ -28,16 +28,18 @@ panel.
 ## What to do if a check failed
 
 If the repository check fails for some repository you should look up the error
-in repocheck.log (in the admin panel or on disk; see
-`/var/log/gitlab/gitlab-rails` for Omnibus installations or
-`/home/git/gitlab/log` for installations from source). Once you have
-resolved the issue use the admin panel to trigger a new repository check on
-the project. This will clear the 'check failed' state.
+in `repocheck.log`:
+
+- in the [admin panel](logs.md#repocheck.log)
+- or on disk, see:
+    - `/var/log/gitlab/gitlab-rails` for Omnibus installations
+    - `/home/git/gitlab/log` for installations from source
 
 If for some reason the periodic repository check caused a lot of false
-alarms you can choose to clear ALL repository check states from the
-'Settings' page of the admin panel.
+alarms you can choose to clear *all* repository check states by
+clicking "Clear all repository checks" on the **Settings** page of the
+admin panel (`/admin/application_settings`).
 
 ---
 [ce-3232]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3232 "Auto git fsck"
-[git-fsck]: https://www.kernel.org/pub/software/scm/git/docs/git-fsck.html "git fsck documentation"
+[git-fsck]: https://git-scm.com/docs/git-fsck "git fsck documentation"
diff --git a/spec/workers/admin_email_worker_spec.rb b/spec/workers/admin_email_worker_spec.rb
new file mode 100644
index 00000000000..27687f069ea
--- /dev/null
+++ b/spec/workers/admin_email_worker_spec.rb
@@ -0,0 +1,41 @@
+require 'spec_helper'
+
+describe AdminEmailWorker do
+  subject(:worker) { described_class.new }
+
+  describe '.perform' do
+    it 'does not attempt to send repository check mail when they are disabled' do
+      stub_application_setting(repository_checks_enabled: false)
+
+      expect(worker).not_to receive(:send_repository_check_mail)
+
+      worker.perform
+    end
+
+    context 'repository_checks enabled' do
+      before do
+        stub_application_setting(repository_checks_enabled: true)
+      end
+
+      it 'checks if repository check mail should be sent' do
+        expect(worker).to receive(:send_repository_check_mail)
+
+        worker.perform
+      end
+
+      it 'does not send mail when there are no failed repos' do
+        expect(RepositoryCheckMailer).not_to receive(:notify)
+
+        worker.perform
+      end
+
+      it 'send mail when there is a failed repo' do
+        create(:project, last_repository_check_failed: true, last_repository_check_at: Date.yesterday)
+
+        expect(RepositoryCheckMailer).to receive(:notify).and_return(spy)
+
+        worker.perform
+      end
+    end
+  end
+end
diff --git a/spec/workers/repository_check/batch_worker_spec.rb b/spec/workers/repository_check/batch_worker_spec.rb
index 850b8cd8f5c..6cd27d2fafb 100644
--- a/spec/workers/repository_check/batch_worker_spec.rb
+++ b/spec/workers/repository_check/batch_worker_spec.rb
@@ -31,8 +31,8 @@ describe RepositoryCheck::BatchWorker do
 
   it 'does nothing when repository checks are disabled' do
     create(:project, created_at: 1.week.ago)
-    current_settings = double('settings', repository_checks_enabled: false)
-    expect(subject).to receive(:current_settings) { current_settings }
+
+    stub_application_setting(repository_checks_enabled: false)
 
     expect(subject.perform).to eq(nil)
   end
diff --git a/spec/workers/repository_check/single_repository_worker_spec.rb b/spec/workers/repository_check/single_repository_worker_spec.rb
index 1d9bbf2ca62..a021235aed6 100644
--- a/spec/workers/repository_check/single_repository_worker_spec.rb
+++ b/spec/workers/repository_check/single_repository_worker_spec.rb
@@ -2,44 +2,60 @@ require 'spec_helper'
 require 'fileutils'
 
 describe RepositoryCheck::SingleRepositoryWorker do
-  subject { described_class.new }
+  subject(:worker) { described_class.new }
 
-  it 'passes when the project has no push events' do
-    project = create(:project_empty_repo, :wiki_disabled)
+  it 'skips when the project has no push events' do
+    project = create(:project, :repository, :wiki_disabled)
     project.events.destroy_all
-    break_repo(project)
+    break_project(project)
 
-    subject.perform(project.id)
+    expect(worker).not_to receive(:git_fsck)
+
+    worker.perform(project.id)
 
     expect(project.reload.last_repository_check_failed).to eq(false)
   end
 
   it 'fails when the project has push events and a broken repository' do
-    project = create(:project_empty_repo)
+    project = create(:project, :repository)
     create_push_event(project)
-    break_repo(project)
+    break_project(project)
 
-    subject.perform(project.id)
+    worker.perform(project.id)
 
     expect(project.reload.last_repository_check_failed).to eq(true)
   end
 
+  it 'succeeds when the project repo is valid' do
+    project = create(:project, :repository, :wiki_disabled)
+    create_push_event(project)
+
+    expect(worker).to receive(:git_fsck).and_call_original
+
+    expect do
+      worker.perform(project.id)
+    end.to change { project.reload.last_repository_check_at }
+
+    expect(project.reload.last_repository_check_failed).to eq(false)
+  end
+
   it 'fails if the wiki repository is broken' do
-    project = create(:project_empty_repo, :wiki_enabled)
+    project = create(:project, :repository, :wiki_enabled)
     project.create_wiki
+    create_push_event(project)
 
     # Test sanity: everything should be fine before the wiki repo is broken
-    subject.perform(project.id)
+    worker.perform(project.id)
     expect(project.reload.last_repository_check_failed).to eq(false)
 
     break_wiki(project)
-    subject.perform(project.id)
+    worker.perform(project.id)
 
     expect(project.reload.last_repository_check_failed).to eq(true)
   end
 
   it 'skips wikis when disabled' do
-    project = create(:project_empty_repo, :wiki_disabled)
+    project = create(:project, :wiki_disabled)
     # Make sure the test would fail if the wiki repo was checked
     break_wiki(project)
 
@@ -49,8 +65,8 @@ describe RepositoryCheck::SingleRepositoryWorker do
   end
 
   it 'creates missing wikis' do
-    project = create(:project_empty_repo, :wiki_enabled)
-    FileUtils.rm_rf(wiki_path(project))
+    project = create(:project, :wiki_enabled)
+    Gitlab::Shell.new.rm_directory(project.repository_storage, project.wiki.path)
 
     subject.perform(project.id)
 
@@ -58,34 +74,39 @@ describe RepositoryCheck::SingleRepositoryWorker do
   end
 
   it 'does not create a wiki if the main repo does not exist at all' do
-    project = create(:project_empty_repo)
-    create_push_event(project)
-    FileUtils.rm_rf(project.repository.path_to_repo)
-    FileUtils.rm_rf(wiki_path(project))
+    project = create(:project, :repository)
+    Gitlab::Shell.new.rm_directory(project.repository_storage, project.path)
+    Gitlab::Shell.new.rm_directory(project.repository_storage, project.wiki.path)
 
     subject.perform(project.id)
 
-    expect(File.exist?(wiki_path(project))).to eq(false)
-  end
-
-  def break_wiki(project)
-    objects_dir = wiki_path(project) + '/objects'
-
-    # Replace the /objects directory with a file so that the repo is
-    # invalid, _and_ 'git init' cannot fix it.
-    FileUtils.rm_rf(objects_dir)
-    FileUtils.touch(objects_dir) if File.directory?(wiki_path(project))
-  end
-
-  def wiki_path(project)
-    project.wiki.repository.path_to_repo
+    expect(Gitlab::Shell.new.exists?(project.repository_storage, project.wiki.path)).to eq(false)
   end
 
   def create_push_event(project)
     project.events.create(action: Event::PUSHED, author_id: create(:user).id)
   end
 
-  def break_repo(project)
-    FileUtils.rm_rf(File.join(project.repository.path_to_repo, 'objects'))
+  def break_wiki(project)
+    break_repo(wiki_path(project))
+  end
+
+  def wiki_path(project)
+    project.wiki.repository.path_to_repo
+  end
+
+  def break_project(project)
+    break_repo(project.repository.path_to_repo)
+  end
+
+  def break_repo(repo)
+    # Create or replace blob ffffffffffffffffffffffffffffffffffffffff with an empty file
+    # This will make the repo invalid, _and_ 'git init' cannot fix it.
+    path = File.join(repo, 'objects', 'ff')
+    file = File.join(path, 'ffffffffffffffffffffffffffffffffffffff')
+
+    FileUtils.mkdir_p(path)
+    FileUtils.rm_f(file)
+    FileUtils.touch(file)
   end
 end