diff --git a/services/mirror/mirror.go b/services/mirror/mirror.go
index 7c12aa085..75054b690 100644
--- a/services/mirror/mirror.go
+++ b/services/mirror/mirror.go
@@ -157,6 +157,25 @@ func parseRemoteUpdateOutput(output string) []*mirrorSyncResult {
 				refName:     refName,
 				newCommitID: gitShortEmptySha,
 			})
+		case strings.HasPrefix(lines[i], " + "): // Force update
+			if idx := strings.Index(refName, " "); idx > -1 {
+				refName = refName[:idx]
+			}
+			delimIdx := strings.Index(lines[i][3:], " ")
+			if delimIdx == -1 {
+				log.Error("SHA delimiter not found: %q", lines[i])
+				continue
+			}
+			shas := strings.Split(lines[i][3:delimIdx+3], "...")
+			if len(shas) != 2 {
+				log.Error("Expect two SHAs but not what found: %q", lines[i])
+				continue
+			}
+			results = append(results, &mirrorSyncResult{
+				refName:     refName,
+				oldCommitID: shas[0],
+				newCommitID: shas[1],
+			})
 		case strings.HasPrefix(lines[i], "   "): // New commits of a reference
 			delimIdx := strings.Index(lines[i][3:], " ")
 			if delimIdx == -1 {
@@ -187,6 +206,7 @@ func runSync(m *models.Mirror) ([]*mirrorSyncResult, bool) {
 	wikiPath := m.Repo.WikiPath()
 	timeout := time.Duration(setting.Git.Timeout.Mirror) * time.Second
 
+	log.Trace("SyncMirrors [repo: %-v]: running git remote update...", m.Repo)
 	gitArgs := []string{"remote", "update"}
 	if m.EnablePrune {
 		gitArgs = append(gitArgs, "--prune")
@@ -228,17 +248,21 @@ func runSync(m *models.Mirror) ([]*mirrorSyncResult, bool) {
 		log.Error("OpenRepository: %v", err)
 		return nil, false
 	}
+
+	log.Trace("SyncMirrors [repo: %-v]: syncing releases with tags...", m.Repo)
 	if err = repo_module.SyncReleasesWithTags(m.Repo, gitRepo); err != nil {
 		gitRepo.Close()
 		log.Error("Failed to synchronize tags to releases for repository: %v", err)
 	}
 	gitRepo.Close()
 
+	log.Trace("SyncMirrors [repo: %-v]: updating size of repository", m.Repo)
 	if err := m.Repo.UpdateSize(models.DefaultDBContext()); err != nil {
 		log.Error("Failed to update size for mirror repository: %v", err)
 	}
 
 	if m.Repo.HasWiki() {
+		log.Trace("SyncMirrors [repo: %-v Wiki]: running git remote update...", m.Repo)
 		stderrBuilder.Reset()
 		stdoutBuilder.Reset()
 		if err := git.NewCommand("remote", "update", "--prune").
@@ -268,8 +292,10 @@ func runSync(m *models.Mirror) ([]*mirrorSyncResult, bool) {
 			}
 			return nil, false
 		}
+		log.Trace("SyncMirrors [repo: %-v Wiki]: git remote update complete", m.Repo)
 	}
 
+	log.Trace("SyncMirrors [repo: %-v]: invalidating mirror branch caches...", m.Repo)
 	branches, err := repo_module.GetBranches(m.Repo)
 	if err != nil {
 		log.Error("GetBranches: %v", err)
@@ -371,11 +397,13 @@ func syncMirror(repoID string) {
 
 	}
 
+	log.Trace("SyncMirrors [repo: %-v]: Running Sync", m.Repo)
 	results, ok := runSync(m)
 	if !ok {
 		return
 	}
 
+	log.Trace("SyncMirrors [repo: %-v]: Scheduling next update", m.Repo)
 	m.ScheduleNextUpdate()
 	if err = models.UpdateMirror(m); err != nil {
 		log.Error("UpdateMirror [%s]: %v", repoID, err)
@@ -384,8 +412,9 @@ func syncMirror(repoID string) {
 
 	var gitRepo *git.Repository
 	if len(results) == 0 {
-		log.Trace("SyncMirrors [repo_id: %d]: no commits fetched", m.RepoID)
+		log.Trace("SyncMirrors [repo: %-v]: no branches updated", m.Repo)
 	} else {
+		log.Trace("SyncMirrors [repo: %-v]: %d branches updated", m.Repo, len(results))
 		gitRepo, err = git.OpenRepository(m.Repo.RepoPath())
 		if err != nil {
 			log.Error("OpenRepository [%d]: %v", m.RepoID, err)
@@ -440,6 +469,7 @@ func syncMirror(repoID string) {
 
 		notification.NotifySyncPushCommits(m.Repo.MustOwner(), m.Repo, result.refName, oldCommitID, newCommitID, theCommits)
 	}
+	log.Trace("SyncMirrors [repo: %-v]: done notifying updated branches/tags - now updating last commit time", m.Repo)
 
 	// Get latest commit date and update to current repository updated time
 	commitDate, err := git.GetLatestCommitTime(m.Repo.RepoPath())
@@ -452,6 +482,8 @@ func syncMirror(repoID string) {
 		log.Error("Update repository 'updated_unix' [%d]: %v", m.RepoID, err)
 		return
 	}
+
+	log.Trace("SyncMirrors [repo: %-v]: Successfully updated", m.Repo)
 }
 
 // InitSyncMirrors initializes a go routine to sync the mirrors