Check rsync destination capacity before copying

dist/urbm-2026.06.15.r017-x86_64-1.txz.sha256

@@ -1 +0,0 @@
-c4a3955c26ca3e380ae25c93d9d3e5706c65f4457ec6d1418cc1ed72b485cb9b  urbm-2026.06.15.r017-x86_64-1.txz

dist/urbm-2026.06.15.r018-x86_64-1.txz.sha256

@@ -0,0 +1 @@
+56f07ac0a18bf9067c8cb38ef6e5cbf69d52a2313e37f32f87b619268a47d6e8  urbm-2026.06.15.r018-x86_64-1.txz

dist/urbm.plg

@@ -2,13 +2,18 @@
 <!DOCTYPE PLUGIN [
 <!ENTITY name "urbm">
 <!ENTITY author "Michael Roll">
-<!ENTITY version "2026.06.15.r017">
+<!ENTITY version "2026.06.15.r018">
 <!ENTITY pluginURL "https://git.casaderoll.de/michael/URBM/raw/branch/main/dist/urbm.plg">
 <!ENTITY packageURL "https://git.casaderoll.de/michael/URBM/raw/branch/main/dist/urbm-&version;-x86_64-1.txz">
-<!ENTITY packageSHA256 "c4a3955c26ca3e380ae25c93d9d3e5706c65f4457ec6d1418cc1ed72b485cb9b">
+<!ENTITY packageSHA256 "56f07ac0a18bf9067c8cb38ef6e5cbf69d52a2313e37f32f87b619268a47d6e8">
 ]>
 <PLUGIN name="&name;" author="&author;" version="&version;" pluginURL="&pluginURL;" min="7.0.0" support="https://git.casaderoll.de/michael/URBM/issues" icon="urbm.png">
   <CHANGES>
+### 2026.06.15.r018
+- Run a write-free Rsync preflight to estimate the actual transfer size before copying.
+- Abort Rsync jobs when the estimated transfer exceeds the free destination capacity.
+- Add an explicitly confirmed override for advanced replacement scenarios where existing destination files will release enough space.
+
 ### 2026.06.15.r017
 - Add scheduled Rsync copy jobs with separate source and destination folder browsers.
 - Add explicit controls for overwrite behavior, destination deletion, permissions, ownership, timestamps, links, ACLs, extended attributes, checksums, and dry runs.

internal/model/model.go

@@ -80,6 +80,7 @@ type RsyncOptions struct {
 	PreserveXattrs      bool   `json:"preserveXattrs"`
 	Checksum            bool   `json:"checksum"`
 	DryRun              bool   `json:"dryRun"`
+	SkipSpaceCheck      bool   `json:"skipSpaceCheck"`
 }
 
 type Source struct {

internal/rsync/rsync.go

@@ -108,6 +108,68 @@ func (r *Runner) Run(ctx context.Context, runID string, job model.Job, callback
 	return summary, nil
 }
 
+// Estimate performs rsync's complete comparison without writing destination data.
+func (r *Runner) Estimate(ctx context.Context, runID string, job model.Job) (Summary, error) {
+	job.Rsync.DryRun = true
+	args := Arguments(job)
+	for index, arg := range args {
+		if strings.HasPrefix(arg, "--out-format=") {
+			args[index] = "--out-format="
+		}
+	}
+	cmd := exec.CommandContext(ctx, r.Binary, args...)
+	cmd.Env = append(os.Environ(), "LC_ALL=C", "LANG=C")
+	cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	cmd.Cancel = func() error {
+		if cmd.Process == nil {
+			return os.ErrProcessDone
+		}
+		if err := syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL); err != nil && !errors.Is(err, syscall.ESRCH) {
+			return err
+		}
+		return nil
+	}
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		return Summary{}, err
+	}
+	stderr, err := cmd.StderrPipe()
+	if err != nil {
+		return Summary{}, err
+	}
+	if err := cmd.Start(); err != nil {
+		if errors.Is(err, exec.ErrNotFound) {
+			return Summary{}, fmt.Errorf("environment: rsync binary not found: %w", err)
+		}
+		return Summary{}, err
+	}
+	unregister := r.register(runID, cmd.Process)
+	defer unregister()
+	var summary Summary
+	done := make(chan struct{})
+	go func() {
+		scanOutput(stdout, func(line string) {
+			if value, ok := parseCount(filesPattern, line); ok {
+				summary.Files = value
+			}
+			if value, ok := parseCount(bytesPattern, line); ok {
+				summary.Bytes = value
+			}
+		})
+		close(done)
+	}()
+	errBytes, _ := io.ReadAll(io.LimitReader(stderr, 1024*1024))
+	err = cmd.Wait()
+	<-done
+	if err != nil {
+		if errors.Is(ctx.Err(), context.Canceled) {
+			return Summary{}, fmt.Errorf("cancelled: %w", ctx.Err())
+		}
+		return Summary{}, fmt.Errorf("rsync preflight: %s", strings.TrimSpace(string(errBytes)))
+	}
+	return summary, nil
+}
+
 func Arguments(job model.Job) []string {
 	options := job.Rsync
 	args := []string{"--recursive", "--human-readable", "--info=progress2", "--stats", "--partial", "--out-format=FILE|%n"}

internal/service/service.go

@@ -11,6 +11,7 @@ import (
 	"path/filepath"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 
 	"git.casaderoll.de/michael/urbm/internal/model"
@@ -402,6 +403,23 @@ func (s *Service) executeRsync(ctx context.Context, run model.Run) (result model
 		}
 		return failed(run, "environment", "rsync target unavailable: "+err.Error())
 	}
+	if !job.Rsync.DryRun && !job.Rsync.SkipSpaceCheck {
+		appendLiveLog(&live, "Rsync-Vorabprüfung ermittelt den tatsächlich zu übertragenden Datenumfang")
+		s.updateActive(live)
+		estimate, err := s.rsync.Estimate(ctx, run.ID, job)
+		if err != nil {
+			return failedError(run, err)
+		}
+		available, err := availableBytes(job.Rsync.Target)
+		if err != nil {
+			return failed(run, "environment", "read rsync target capacity: "+err.Error())
+		}
+		appendLiveLog(&live, fmt.Sprintf("Rsync-Vorabprüfung: %s zu übertragen, %s am Ziel frei", formatBytes(estimate.Bytes), formatBytes(available)))
+		s.updateActive(live)
+		if estimate.Bytes > available {
+			return failed(run, "environment", fmt.Sprintf("Rsync-Ziel hat nicht genügend freien Speicher: ungefähr %s für %d Dateien erforderlich, aber nur %s frei unter %s", formatBytes(estimate.Bytes), estimate.Files, formatBytes(available), job.Rsync.Target))
+		}
+	}
 	started := time.Now()
 	lastLoggedPercent := -10
 	summary, err := s.rsync.Run(ctx, run.ID, job, func(progress rsync.Progress) {
@@ -442,6 +460,14 @@ func (s *Service) executeRsync(ctx context.Context, run model.Run) (result model
 	return run
 }
 
+func availableBytes(path string) (int64, error) {
+	var stats syscall.Statfs_t
+	if err := syscall.Statfs(path, &stats); err != nil {
+		return 0, err
+	}
+	return int64(stats.Bavail) * int64(stats.Bsize), nil
+}
+
 func (s *Service) executeBackup(ctx context.Context, run model.Run) (result model.Run) {
 	job, ok := s.job(run.JobID)
 	if !ok {

plugin/urbm.plg

@@ -2,13 +2,18 @@
 <!DOCTYPE PLUGIN [
 <!ENTITY name "urbm">
 <!ENTITY author "Michael Roll">
-<!ENTITY version "2026.06.15.r017">
+<!ENTITY version "2026.06.15.r018">
 <!ENTITY pluginURL "https://git.casaderoll.de/michael/URBM/raw/branch/main/dist/urbm.plg">
 <!ENTITY packageURL "https://git.casaderoll.de/michael/URBM/raw/branch/main/dist/urbm-&version;-x86_64-1.txz">
 <!ENTITY packageSHA256 "REPLACE_DURING_RELEASE">
 ]>
 <PLUGIN name="&name;" author="&author;" version="&version;" pluginURL="&pluginURL;" min="7.0.0" support="https://git.casaderoll.de/michael/URBM/issues" icon="urbm.png">
   <CHANGES>
+### 2026.06.15.r018
+- Run a write-free Rsync preflight to estimate the actual transfer size before copying.
+- Abort Rsync jobs when the estimated transfer exceeds the free destination capacity.
+- Add an explicitly confirmed override for advanced replacement scenarios where existing destination files will release enough space.
+
 ### 2026.06.15.r017
 - Add scheduled Rsync copy jobs with separate source and destination folder browsers.
 - Add explicit controls for overwrite behavior, destination deletion, permissions, ownership, timestamps, links, ACLs, extended attributes, checksums, and dry runs.

webgui/URBM.page

@@ -9,12 +9,12 @@ Tag="URBM Unraid Restic Backup Manager backup snapshots restore"
 <?php
 $pluginRoot = '/plugins/urbm';
 ?>
-<link rel="stylesheet" href="<?= $pluginRoot ?>/assets/urbm.css?v=20260615r017">
+<link rel="stylesheet" href="<?= $pluginRoot ?>/assets/urbm.css?v=20260615r018">
 <div id="urbm-app" data-api="<?= $pluginRoot ?>/api.php">
   <header class="bu-header">
     <div class="bu-brand">
-      <img class="bu-logo" src="<?= $pluginRoot ?>/images/urbm.png?v=20260615r017" alt="URBM-Logo">
+      <img class="bu-logo" src="<?= $pluginRoot ?>/images/urbm.png?v=20260615r018" alt="URBM-Logo">
-      <div><h1>URBM <span class="bu-version">2026.06.15.r017</span></h1><p>Restic Backup Manager für Unraid</p></div>
+      <div><h1>URBM <span class="bu-version">2026.06.15.r018</span></h1><p>Restic Backup Manager für Unraid</p></div>
     </div>
     <div id="bu-health" class="bu-health" tabindex="0" data-tooltip="Zeigt, ob die URBM-Hintergrundkomponente erreichbar ist. Beispiel: 'Daemon online' bedeutet, dass Jobs gestartet werden können.">Verbindung wird hergestellt...</div>
   </header>
@@ -32,4 +32,4 @@ $pluginRoot = '/plugins/urbm';
   <div id="bu-tooltip" role="tooltip" aria-hidden="true"></div>
 </div>
 <script>window.URBM_CSRF = <?= json_encode($var['csrf_token'] ?? '') ?>;</script>
-<script src="<?= $pluginRoot ?>/assets/urbm-2026.06.15.r017.js"></script>
+<script src="<?= $pluginRoot ?>/assets/urbm-2026.06.15.r018.js"></script>

webgui/assets/urbm.js

@@ -409,6 +409,7 @@
     } else if (type === 'rsync') {
       const o=job.rsync||{};
       host.innerHTML = `<h3>Direkte Rsync-Kopie</h3><div class="bu-inline-info">Rsync erstellt keine verschlüsselten Snapshots. Die ausgewählten Ordner werden direkt in das Ziel kopiert. Die Option „Am Ziel löschen“ spiegelt Löschungen und sollte bewusst aktiviert werden.</div><div id="bu-source-browser"></div><label class="bu-manual-source">Zusätzliche manuelle Quellpfade<textarea name="sources"></textarea></label><h3>Zielordner</h3><label class="wide">Rsync-Ziel<input name="rsyncTarget" required value="${esc(o.target||'')}" placeholder="/mnt/remotes/backup"></label><div id="bu-rsync-target-browser"></div><fieldset class="wide bu-fieldset"><legend>Rsync-Optionen</legend><div class="bu-event-options"><label><input name="rsyncOverwrite" type="checkbox" ${o.overwrite!==false?'checked':''}><span>Vorhandene Dateien aktualisieren / überschreiben</span></label><label><input name="rsyncDelete" type="checkbox" ${o.delete===true?'checked':''}><span>Dateien am Ziel löschen, die in der Quelle nicht mehr vorhanden sind</span></label><label><input name="rsyncPermissions" type="checkbox" ${o.preservePermissions!==false?'checked':''}><span>Dateiberechtigungen übernehmen</span></label><label><input name="rsyncOwner" type="checkbox" ${o.preserveOwner===true?'checked':''}><span>Besitzer übernehmen</span></label><label><input name="rsyncGroup" type="checkbox" ${o.preserveGroup===true?'checked':''}><span>Gruppen übernehmen</span></label><label><input name="rsyncTimes" type="checkbox" ${o.preserveTimes!==false?'checked':''}><span>Zeitstempel übernehmen</span></label><label><input name="rsyncLinks" type="checkbox" ${o.preserveLinks!==false?'checked':''}><span>Symbolische Links als Links übernehmen</span></label><label><input name="rsyncACLs" type="checkbox" ${o.preserveAcls===true?'checked':''}><span>ACLs übernehmen</span></label><label><input name="rsyncXattrs" type="checkbox" ${o.preserveXattrs===true?'checked':''}><span>Erweiterte Attribute übernehmen</span></label><label><input name="rsyncChecksum" type="checkbox" ${o.checksum===true?'checked':''}><span>Dateien per Prüfsumme vergleichen (langsamer)</span></label><label><input name="rsyncDryRun" type="checkbox" ${o.dryRun===true?'checked':''}><span>Testlauf ohne Änderungen</span></label></div></fieldset>`;
+      host.querySelector('.bu-event-options').insertAdjacentHTML('beforeend', `<label><input name="rsyncSkipSpaceCheck" type="checkbox" ${o.skipSpaceCheck===true?'checked':''}><span>Kapazitätsprüfung überspringen (riskant; nur wenn vorhandene Zieldateien ausreichend Platz freigeben)</span></label>`);
       state.sourceBrowserPath='/'; state.sourceDirectories=sourceRoots; state.sourceBrowserError=''; renderSourceBrowser(); renderRsyncTargetBrowser();
     } else {
       state.backupSelections = ['/boot'];
@@ -668,9 +669,10 @@
       else sources=[...state.backupSelections.map(path=>({path})),...lines(f.get('sources')||'').map(path=>({path}))].filter((item,index,all)=>all.findIndex(other=>other.path===item.path)===index);
       const retention={keepWithinDays:Number(f.get('keepWithinDays')),daily:Number(f.get('keepDaily')),weekly:Number(f.get('keepWeekly')),monthly:Number(f.get('keepMonthly'))};
       if(type!=='rsync'&&!retention.keepWithinDays&&!retention.daily&&!retention.weekly&&!retention.monthly) throw new Error('Die Aufbewahrung benötigt mindestens eine Alters- oder Kalenderregel.');
-      const rsync=type==='rsync'?{target:String(f.get('rsyncTarget')||'').trim(),overwrite:f.get('rsyncOverwrite')==='on',delete:f.get('rsyncDelete')==='on',preservePermissions:f.get('rsyncPermissions')==='on',preserveOwner:f.get('rsyncOwner')==='on',preserveGroup:f.get('rsyncGroup')==='on',preserveTimes:f.get('rsyncTimes')==='on',preserveLinks:f.get('rsyncLinks')==='on',preserveAcls:f.get('rsyncACLs')==='on',preserveXattrs:f.get('rsyncXattrs')==='on',checksum:f.get('rsyncChecksum')==='on',dryRun:f.get('rsyncDryRun')==='on'}:{};
+      const rsync=type==='rsync'?{target:String(f.get('rsyncTarget')||'').trim(),overwrite:f.get('rsyncOverwrite')==='on',delete:f.get('rsyncDelete')==='on',preservePermissions:f.get('rsyncPermissions')==='on',preserveOwner:f.get('rsyncOwner')==='on',preserveGroup:f.get('rsyncGroup')==='on',preserveTimes:f.get('rsyncTimes')==='on',preserveLinks:f.get('rsyncLinks')==='on',preserveAcls:f.get('rsyncACLs')==='on',preserveXattrs:f.get('rsyncXattrs')==='on',checksum:f.get('rsyncChecksum')==='on',dryRun:f.get('rsyncDryRun')==='on',skipSpaceCheck:f.get('rsyncSkipSpaceCheck')==='on'}:{};
       if(type==='rsync'&&!rsync.target) throw new Error('Wähle einen Zielordner für die Rsync-Kopie.');
       if(type==='rsync'&&rsync.delete&&!confirm('Rsync darf Dateien am Ziel löschen, die in der Quelle nicht mehr vorhanden sind. Diese Option kann Daten am Ziel entfernen. Wirklich speichern?')) return;
+      if(type==='rsync'&&rsync.skipSpaceCheck&&!confirm('Die Kapazitätsprüfung wirklich abschalten? Der Rsync-Lauf kann dann das Ziel vollständig füllen und mit einem Schreibfehler abbrechen.')) return;
       const job={schemaVersion:1,id:f.get('id')||id('job'),name:f.get('name'),type,enabled:f.get('enabled')==='on',repositoryId:type==='rsync'?'':f.get('repositoryId'),sources,schedule:{cron:scheduleCron(f),timezone:Intl.DateTimeFormat().resolvedOptions().timeZone},consistency:{mode:f.get('consistency')||'live'},compression:type==='rsync'?'':f.get('compression'),cpuCores:type==='rsync'?0:Number(f.get('cpuCores')||0),excludes:lines(f.get('excludes')),tags:existing?.tags||[],flashImage:type==='flash'&&f.get('flashImage')==='on',retention:type==='rsync'?{}:retention,rsync,notifyOn:existing?.notifyOn||['success','warning','failed'],shutdownTimeoutSeconds:Number(f.get('shutdownSecs')||120)};
       state.config.jobs=state.config.jobs.filter(j=>j.id!==job.id).concat(job); await saveConfig(); render();
     }