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Checksum-Verified Cloud Migrations with RcloneView (Drive, Dropbox, S3, R2)

· 4 min read
Tayson
Tayson
Senior Engineer

Move petabytes only once. Use RcloneView to sync, verify with checksums, and catch drift before you switch apps over.

Copying from Google Drive to Dropbox or S3 to R2 is easy—proving every object arrived intact is harder. Rclone has battle-tested checksum and compare modes; RcloneView wraps them in a GUI so you can run integrity-checked migrations with schedules, logs, and zero shell scripts.

Relevant docs

RcloneView app preview

Manage & Sync All Clouds in One Place

RcloneView is a cross-platform GUI for rclone. Compare folders, transfer or sync files, and automate multi-cloud workflows with a clean, visual interface.

  • One-click jobs: Copy · Sync · Compare
  • Schedulers & history for reliable automation
  • Works with Google Drive, OneDrive, Dropbox, S3, WebDAV, SFTP and more
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Free core features. Plus automations available.

Why checksum-verified migrations​

  • Avoid silent corruption: checksums detect bitrot and partial uploads.
  • Faster cutovers: Compare highlights mismatches before you flip endpoints.
  • Multi-cloud ready: Works across Drive, Dropbox, OneDrive, S3, Wasabi, R2, B2, and NAS.
  • Zero scripting: Build, schedule, and re-run jobs visually.

Migration blueprint​

[Source cloud/NAS] --(RcloneView Sync with --checksum)--> [Target cloud]
                                           \
                                            --(RcloneView Compare)--> [Drift report]
  • Stage 1: Baseline Sync with checksum to upload everything once.
  • Stage 2: Incremental Syncs on a schedule to shrink cutover window.
  • Stage 3: Compare to confirm object counts and hashes match.
  • Stage 4: Cutover/Mount the target for production use.

Prerequisites​

  • Remotes added in RcloneView for both source and target (e.g., drive:team, dropbox:prod, s3:archive, r2:mirror).
  • Target has enough quota and, if S3-compatible, versioning enabled for safety.
  • API/IAM keys allow list/read/write and, for S3, multipart uploads.

Step 1: Create a checksum Sync job​

  1. New Sync job: Source = current system, Destination = target cloud.
  2. Open Advanced Options and enable checksum verification:
--checksum --checkers=8 --transfers=8 --s3-chunk-size=64M --s3-upload-concurrency=8
  1. Add include/exclude filters for cache/temp folders.
  2. Save the job so reruns keep the same integrity flags.

Step 2: Schedule incremental runs​

  1. Open Scheduler > select the migration job.
  2. Run nightly or hourly to reduce the final cutover delta.
  3. Enable retries/backoff to ride through throttling.
  4. Turn on logging for audit and rollback notes.
Configure the job scheduler in RcloneView

Step 3: Verify with Compare​

  • After the baseline, run Compare between source and target with --checksum to validate content, not just size.
  • Use the weekly scheduled Compare pattern from the scheduler to catch late drift.
  • Check the report/logs for mismatches; re-run Sync to fix only the differences.

Step 4: Cutover safely​

  1. Freeze writes on the source (maintenance window).
  2. Run a final Sync with --checksum --fast-list to close the gap.
  3. Run Compare one last time; expect zero mismatches.
  4. Mount the target in RcloneView so apps/users can validate paths before DNS/endpoint changes.
--dry-run --checksum --no-traverse  # quick validation before cutover

Tuning tips​

  • High latency links: lower --s3-upload-concurrency; increase --s3-chunk-size for large media.
  • Mixed clouds: if a provider lacks checksums, pair --checksum with --size-only fallback cautiously.
  • Bandwidth caps: set --bwlimit during business hours; schedule heavier runs overnight.
  • Safety net: keep versioning/object lock on the target if ransomware is a concern.

Troubleshooting checklist​

  • Mismatch counts: rerun Compare with --checksum; verify both sides expose hashes (MD5/SHA/Dropbox content hash).
  • Slow verifies: reduce --checkers or use --fast-list where supported.
  • AccessDenied on S3 uploads: ensure multipart and list permissions are granted.
  • Deleted files reappear: remove delete flags only after the final cutover if you need strict mirroring.

Quick-start template​

Job: Checksum Migration (Drive -> R2)
Source: drive:marketing-hub
Destination: r2:global-marketing
Flags:
  --checksum
  --checkers=8
  --transfers=8
  --s3-chunk-size=64M
  --s3-upload-concurrency=8
Schedule: Nightly at 01:00, 2 retries with 10m backoff
Verification: Weekly Compare with --checksum + email notification on mismatch
Cutover: Final Sync + Compare, then Mount r2:global-marketing for validation

Checksum every migration, and you only have to move the data once.