added -checksum and -passes parameters, added logic to skip checksum, added logic to limit max passes, print configuration on startup, added help message

README.md

@@ -46,15 +46,34 @@ Due to the working principle of this script, it is crucial that you **only run i
 
 **ALWAYS HAVE A BACKUP OF YOUR DATA!**
 
+You can print a help message by running the script without any parameters:
+
 ```
 chmod +x ./zfs-inplace-rebalancing.sh
-./zfs-inplace-rebalancing.sh /pool/path/to/rebalance
+./zfs-inplace-rebalancing.sh
 ```
 
+### Parameters
+
+| Name      | Description | Default |
+|-----------|-------------|---------|
+| -checksum | Whether to compare the copy using an **MD5** checksum | `true` |
+| -passes   | The maximum number of rebalance passes per file | `1` |
+
+### Example
+
+```
+./zfs-inplace-rebalancing.sh -checksum true -passes 1 /pool/path/to/rebalance
+```
+
+### Things to consider
+
 Although this script **does** have a progress output (files as well as percentage) it might be a good idea to try a small subfolder first, or process your pool folder layout in manually selected badges. This can also limit the damage done, if anything bad happens.
 
 When aborting the script midway through, be sure to check the last lines of its output. When cancelling before or during the renaming process a ".rebalance" file might be left and you have to rename it manually.
 
+Although the `-passes` paramter can be used to limit the maximum amount of rebalance passes per file, it is only meant to speedup aborted runs. Individual files will **not be process multiple times automatically**. To reach multiple passes you have to run the script on the same target directory multiple times.
+
 ## Attributions
 
 This script was inspired by [zfs-balancer](https://github.com/programster/zfs-balancer).

zfs-inplace-rebalancing.sh

@@ -17,7 +17,6 @@ current_index=0
 Color_Off='\033[0m'       # Text Reset
 
 # Regular Colors
-Black='\033[0;30m'        # Black
 Red='\033[0;31m'          # Red
 Green='\033[0;32m'        # Green
 Yellow='\033[0;33m'       # Yellow
@@ -25,6 +24,11 @@ Cyan='\033[0;36m'         # Cyan
 
 ## Functions
 
+# print a help message
+function print_usage() {
+  echo "Usage: zfs-inplace-rebalancing -checksum true -passes 1 /my/pool"
+}
+
 # print a given text entirely in a given color
 function color_echo () {
     color=$1
@@ -32,13 +36,36 @@ function color_echo () {
     echo -e "${color}${text}${Color_Off}"
 }
 
+
+function get_rebalance_count () {
+    file_path=$1
+
+    line_nr=$(grep -n "${file_path}" "./${rebalance_db_file_name}" | head -n 1 | cut -d: -f1)
+    if [ -z "${line_nr}" ]; then
+        echo "0"
+        return
+    else
+        rebalance_count_line_nr="$((line_nr + 1))"
+        rebalance_count=$(awk "NR == ${rebalance_count_line_nr}" "./${rebalance_db_file_name}")
+        echo "${rebalance_count}"
+        return
+    fi
+}
+
 # rebalance a specific file
 function rebalance () {
     file_path=$1
 
     current_index="$((current_index + 1))"
     progress_percent=$(echo "scale=2; ${current_index}*100/${file_count}" | bc)
-    color_echo "$Cyan" "Progress -- Files: ${current_index}/${file_count} (${progress_percent}%)" 
+    color_echo "${Cyan}" "Progress -- Files: ${current_index}/${file_count} (${progress_percent}%)" 
+
+    # check if target rebalance count is reached
+    rebalance_count=$(get_rebalance_count "${file_path}")
+    if [ "${rebalance_count}" -ge "${passes_flag}" ]; then
+      color_echo "${Yellow}" "Rebalance count (${passes_flag}) reached, skipping: ${file_path}"
+      return
+    fi
    
     tmp_extension=".balance"
     tmp_file_path="${file_path}${tmp_extension}"
@@ -68,6 +95,7 @@ function rebalance () {
     fi
 
     # compare copy against original to make sure nothing went wrong
+    if [[ "${checksum_flag,,}" == "true"* ]]; then
         echo "Comparing copy against original..."
         if [[ "${OSTYPE,,}" == "linux-gnu"* ]]; then
             # Linux
@@ -85,7 +113,6 @@ function rebalance () {
             copy_md5="${copy_md5} $(ls -lha "${tmp_file_path}" | awk '{print $1 " " $3 " " $4}')"
             # file content
             copy_md5="${copy_md5} $(md5sum -b "${tmp_file_path}" | awk '{print $1}')"
-
         elif [[ "${OSTYPE,,}" == "darwin"* ]] || [[ "${OSTYPE,,}" == "freebsd"* ]]; then
             # Mac OS
             # FreeBSD
@@ -103,7 +130,6 @@ function rebalance () {
             copy_md5="${copy_md5} $(ls -lha "${tmp_file_path}" | awk '{print $1 " " $3 " " $4}')"
             # file content
             copy_md5="${copy_md5} $(md5 -q "${tmp_file_path}")"
-
         else
             echo "Unsupported OS type: $OSTYPE"
             exit 1
@@ -115,6 +141,7 @@ function rebalance () {
             color_echo "${Red}" "MD5 FAILED: ${original_md5} != ${copy_md5}"
             exit 1
         fi
+    fi
 
     echo "Removing original '${file_path}'..."
     rm "${file_path}"
@@ -123,7 +150,6 @@ function rebalance () {
     mv "${tmp_file_path}" "${file_path}"
 
     # update rebalance "database"
-    touch "./${rebalance_db_file_name}"
     line_nr=$(grep -n "${file_path}" "./${rebalance_db_file_name}" | head -n 1 | cut -d: -f1)
     if [ -z "${line_nr}" ]; then
       rebalance_count=1
@@ -131,17 +157,52 @@ function rebalance () {
       echo "${rebalance_count}" >> "./${rebalance_db_file_name}"
     else
       rebalance_count_line_nr="$((line_nr + 1))"
-      rebalance_count=$(awk "NR == ${rebalance_count_line_nr}" "./${rebalance_db_file_name}")
       rebalance_count="$((rebalance_count + 1))"
       sed -i "${rebalance_count_line_nr}s/.*/${rebalance_count}/" "./${rebalance_db_file_name}"
     fi
 }
 
+checksum_flag='true'
+passes_flag='1'
+
+if [ "$#" -eq 0 ]; then
+    print_usage
+    exit 0
+fi
+
+while true ; do
+    case "$1" in
+        -checksum )
+            if [ "$2" -eq 1 ] || [[ "$2" =~ (on|true|yes) ]]; then
+                checksum_flag="true"
+            else
+                checksum_flag="false"
+            fi
+            shift 2
+        ;;
+        -count )
+            passes_flag=$2
+            shift 2
+        ;;
+        *)
+            break
+        ;;
+    esac 
+done;
+
 root_path=$1
 
+color_echo "$Cyan" "Start rebalancing:"
+color_echo "$Cyan" "  Path: ${root_path}"
+color_echo "$Cyan" "  Rebalancing Passes: ${passes_flag}"
+color_echo "$Cyan" "  Use Checksum: ${checksum_flag}"
+
 # count files
-file_count=$(find "$root_path" -type f | wc -l)
+file_count=$(find "${root_path}" -type f | wc -l)
-echo "Files to rebalance: $file_count"
+color_echo "$Cyan" "  File count: ${file_count}"
+
+# create db file
+touch "./${rebalance_db_file_name}"
 
 # recursively scan through files and execute "rebalance" procedure
 find "$root_path" -type f -print0 | while IFS= read -r -d '' file; do rebalance "$file"; done