02. Data Synchronization Deep Dive

Data synchronization is the heart of GarSync. This chapter explains the configuration of sync tasks, how the underlying engine works, and how to use private cloud storage (NAS/SMB) to back up your sports data.

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1. Sync Task Configuration

When creating a task in the "Sync" page, you have several granular options:

Supported Data Types

GarSync goes beyond just activity records. It supports cross-platform syncing for:

• Activity: GPS tracks and metrics for running, cycling, swimming, etc.
• Weight: Body weight, body fat percentage, and other health metrics.
• Route: GPX/TCX files, perfect for transferring routes to your bike computer or watch.
• Training Plan: Keep your calendar and scheduled sessions in sync.
• Workout: Structured intervals or power-based training instructions.
• Sleep: Duration and quality analysis.

Filters and Selection

• Sport Filtering: You can specify to sync only "Running" and "Cycling" while ignoring other activities.
• Time Range: Set "Start Date" and "End Date". This is useful if you only want to sync recent data or perform a bulk migration for a specific period.

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2. Synchronization Mechanism

Intelligent Deduplication

GarSync uses a GUID Matching Strategy based on the activity's Start Time.

• Even if you sync the same activity from Garmin to Strava and then distribute it from Strava to other platforms, GarSync identifies them via the timestamp. It will never create duplicate records.
• If a source activity is edited (e.g., changed title), the system detects the updatedAt change and attempts to update the target platform.

Automation Logic

• Real-time Trigger: With "Auto-Sync" enabled, the system monitors the source account. Once a new upload is detected, the task is queued immediately.
• Background Operation: GarSync supports background persistence on Android. We recommend enabling "Run in Background" in the app settings to ensure syncs complete silently without opening the app.

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3. Private Cloud Backup (NAS/SMB)

GarSync allows you to back up all your sports data to your own NAS or private cloud, giving you true data sovereignty.

Setup Steps

1. Tap "+" in Account Management.
2. Select "SMB/Samba" under the "Storage" category.
3. Enter your NAS address (e.g., 192.168.1.100), port, username, and password.
4. Once verified, create a sync task with this SMB account as the Target.

Archive Format

• Data is stored in its original structure on your NAS.
• GarSync automatically organizes files by year and month, making it easy to access your raw .fit files from any computer.

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4. Troubleshooting

• Sync Failed?
• Tap the task card to view the error log.
• Common cause: "Authorization Expired." Go to Account Management, select the account, and tap "Re-login."
• Missing Data?
• Perform a "Full Refresh" in the account settings. This forces the system to re-scan and match all historical metadata between the source and target.