Add 'resume' capability to parallel-rsync-repos

bin/parallel-rsync-repos

-#!/bin/sh
-# this script should run as the 'git' user, not root, because of mkdir
+#!/usr/bin/env bash
+# this script should run as the 'git' user, not root, because 'root' should not
+# own intermediate directories created by rsync.
 #
 # Example invocation:
 # find /var/opt/gitlab/git-data/repositories -maxdepth 2 | \
-#   parallel-rsync-repos /var/opt/gitlab/git-data/repositories /mnt/gitlab/repositories
+#   parallel-rsync-repos transfer-success.log /var/opt/gitlab/git-data/repositories /mnt/gitlab/repositories
 #
 # You can also rsync to a remote destination.
 #
-# parallel-rsync-repos /var/opt/gitlab/git-data/repositories user@host:/mnt/gitlab/repositories
+# parallel-rsync-repos transfer-success.log /var/opt/gitlab/git-data/repositories user@host:/mnt/gitlab/repositories
 #
 # If you need to pass extra options to rsync, set the RSYNC variable
 #
-# env RSYNC='rsync --rsh="foo bar"' parallel-rsync-repos /src dest
+# env RSYNC='rsync --rsh="foo bar"' parallel-rsync-repos transfer-success.log /src dest
 #
 
-SRC=$1
-DEST=$2
+LOGFILE=$1
+SRC=$2
+DEST=$3
 
-if [ -z "$JOBS" ] ; then
-  JOBS=10
+if [ -z "$LOGFILE" ] || [ -z "$SRC" ] || [ -z "$DEST" ] ; then
+  echo "Usage: $0 LOGFILE SRC DEST"
+  exit 1
 fi
 
-if [ -z "$SRC" ] || [ -z "$DEST" ] ; then
-  echo "Usage: $0 SRC DEST"
-  exit 1
+if [ -z "$JOBS" ] ; then
+  JOBS=10
 fi
 
 if [ -z "$RSYNC" ] ; then
@@ -35,5 +37,18 @@ if ! cd $SRC ; then
   exit 1
 fi
 
-sed "s|$SRC|./|" |\
-  parallel -j$JOBS --progress "mkdir -p $DEST/{} && $RSYNC --delete -a {}/. $DEST/{}/"
+rsyncjob() {
+  relative_dir="./${1#$SRC}"
+
+  if ! $RSYNC --delete --relative -a "$relative_dir" "$DEST" ; then
+    echo "rsync $1 failed"
+    return 1
+  fi
+
+  echo "$1" >> $LOGFILE
+}
+
+export LOGFILE SRC DEST RSYNC
+export -f rsyncjob
+
+parallel -j$JOBS --progress rsyncjob

doc/operations/moving_repositories.md

@@ -96,25 +96,59 @@ after switching to the new repository storage directory.
 
 ### Parallel rsync for all repositories known to GitLab
 
-This will sync repositories with 10 rsync processes at a time.
+This will sync repositories with 10 rsync processes at a time. We keep
+track of progress so that the transfer can be restarted if necessary.
+
+First we create a new directory, owned by 'git', to hold transfer
+logs. We assume the directory is empty before we start the transfer
+procedure, and that we are the only ones writing files in it.
 
 ```
 # Omnibus
-sudo gitlab-rake gitlab:list_repos |\
-  sudo -u git \
+sudo mkdir /var/opt/gitlab/transfer-logs
+sudo chown git:git /var/opt/gitlab/transfer-logs
+
+# Source
+sudo -u git -H mkdir /home/git/transfer-logs
+```
+
+We seed the process with a list of the directories we want to copy.
+
+```
+# Omnibus
+sudo -u git sh -c 'gitlab-rake gitlab:list_repos > /var/opt/gitlab/transfer-logs/all-repos-$(date +%s).txt'
+
+# Source
+cd /home/git/gitlab
+sudo -u git -H sh -c 'bundle exec rake gitlab:list_repos > /home/git/transfer-logs/all-repos-$(date +%s).txt'
+```
+
+Now we can start the transfer. The command below is idempotent, and
+the number of jobs done by GNU Parallel should converge to zero. If it
+does not some repositories listed in all-repos-1234.txt may have been
+deleted/renamed before they could be copied.
+
+```
+# Omnibus
+sudo -u git sh -c '
+cat /var/opt/gitlab/transfer-logs/* | sort | uniq -u |\
   /usr/bin/env JOBS=10 \
-  /opt/gitlab/embedded/service/gitlab-rails/bin/parallel-rsync-repoos \
+  /opt/gitlab/embedded/service/gitlab-rails/bin/parallel-rsync-repos \
+    /var/opt/gitlab/transfer-logs/succes-$(date +%s).log \
     /var/opt/gitlab/git-data/repositories \
     /mnt/gitlab/repositories
+'
 
 # Source
 cd /home/git/gitlab
-sudo -u git -H bundle exec rake gitlab:list_repos |\
-  sudo -u git -H \
+sudo -u git -H sh -c '
+cat /home/git/transfer-logs/* | sort | uniq -u |\
   /usr/bin/env JOBS=10 \
   bin/parallel-rsync-repos \
+    /home/git/transfer-logs/succes-$(date +%s).log \
     /home/git/repositories \
     /mnt/gitlab/repositories
+`
 ```
 
 ### Parallel rsync only for repositories with recent activity
@@ -129,7 +163,8 @@ gitlab:list_repos' to only print repositories with recent activity.
 sudo gitlab-rake gitlab:list_repos SINCE='2015-10-1 12:00 UTC' |\
   sudo -u git \
   /usr/bin/env JOBS=10 \
-  /opt/gitlab/embedded/service/gitlab-rails/bin/parallel-rsync-repoos \
+  /opt/gitlab/embedded/service/gitlab-rails/bin/parallel-rsync-repos \
+    succes-$(date +%s).log \
     /var/opt/gitlab/git-data/repositories \
     /mnt/gitlab/repositories
 
@@ -139,6 +174,7 @@ sudo -u git -H bundle exec rake gitlab:list_repos SINCE='2015-10-1 12:00 UTC' |\
   sudo -u git -H \
   /usr/bin/env JOBS=10 \
   bin/parallel-rsync-repos \
+    succes-$(date +%s).log \
     /home/git/repositories \
     /mnt/gitlab/repositories
 ```