External Storage Guide
Recommended Configuration
| Configuration | Recommended Value | Description |
|---|---|---|
| Capacity | 256 GB or above | Depends on the number of apps and data directories to migrate |
| Interface | USB 3.0 or above / Thunderbolt | USB 2.0 is slow; large app migration takes longer |
| File System | APFS | The only supported format for migrating container data; also supports clones, snapshots, and space sharing, with the best performance |
Interface Performance Comparison
| Interface | Theoretical Speed | Actual Migration Speed | Use Case |
|---|---|---|---|
| USB 2.0 | 480 Mbps | ~30 MB/s | Not recommended; too slow |
| USB 3.0 (USB-A) | 5 Gbps | ~350 MB/s | Basically sufficient |
| USB 3.1 Gen 2 (USB-C) | 10 Gbps | ~700 MB/s | Recommended |
| Thunderbolt 3/4 | 40 Gbps | ~2500 MB/s | Best performance |
| NVMe (Thunderbolt) | 40 Gbps | ~2800 MB/s | Best performance |
File System Recommendations
APFS (Recommended)
- Supports clones, snapshots, space sharing
- Best performance, especially for SSDs
- Native macOS support
- Migrating container data (
~/Library/Containers/, such as WeChat chat history) requires an APFS external drive. See the explanation and experiments in Why External Drives Must Use APFS.
HFS+
- Good compatibility; suitable for older Macs
- Does not support clones and snapshots
- Suitable for mechanical hard drives
exFAT
- Cross-platform compatible (macOS + Windows)
- Does not support hard links and clones
- Relatively lower performance
- Suitable for scenarios requiring use across multiple systems
- Cannot be used for container data migration. If you also need Windows compatibility, use a separate APFS partition for AppPorts. If exFAT occupies the whole drive, the built-in tools cannot shrink it directly; back it up before repartitioning. See Partition requirements and preparation.
Capacity Planning
AppPorts' external storage usage after migration depends on the size of migrated apps and data directories. Below are reference sizes for common apps:
| App Type | Size |
|---|---|
| Chrome | ~500 MB |
| Microsoft Office | ~5 GB |
| Adobe Creative Cloud | ~20-50 GB |
| Xcode | ~15 GB |
| Final Cut Pro | ~5 GB |
| Local large language models (Ollama) | ~4-30 GB |
💡 Capacity Recommendations
- Light use (5-10 apps): 128 GB
- Medium use (10-20 apps): 256 GB
- Heavy use (20+ apps + data directories): 512 GB or above
Notes
- External storage must remain connected; migrated apps and data directories cannot be used offline
- Regularly back up data on external storage
- Avoid unplugging external storage during migration
- Quit apps that use external data before unplugging the drive. For mount-migrated directories, click "Unmount" in AppPorts first.
- Do not manually place regular files at AppPorts external data-directory target paths; AppPorts only relinks or normalizes real directories
- If external storage fails, try moving apps back to this Mac with AppPorts after restoring the connection