When you need to transfer a WeChat archive containing 10GB and 110,000 files between two iPhones, traditional methods often fall short:

• AirDrop: Gets stuck indefinitely on “Preparing files” and never starts transferring
• iCloud: Directly reports an error, unable to handle such a large number of files

This article introduces an efficient solution using a-Shell + SSH + tar.

Why Not Use iSH

You might consider using iSH, a Linux emulator for iOS. However, iSH suffers from severe IO performance bottlenecks when mounting iOS filesystems with mount -t ios.

Performance Issues

iSH’s performance problems stem from its underlying architecture: it fully emulates x86 instruction sets in user space, resulting in significant performance degradation. When using mount -t ios to mount iOS File Provider, it must additionally go through iOS’s filesystem API layer, further increasing IO overhead.

Speed Performance

According to user reports, iSH runs orders of magnitude slower than native execution. Developers have stated that even with code improvements, commands like youtube-dl --help still take about a minute to complete, making it difficult to optimize below 10 seconds. These limitations are equally apparent when working with mounted iOS filesystems.

JIT Optimization Attempts

The development team attempted to introduce JIT (Just-In-Time compilation) to improve performance by 2-5x, but Apple rejected this request. Currently on iOS, users must choose between flexibility (iSH’s complete shell environment) and performance (native solutions like a-Shell).

Choosing a-Shell

a-Shell is a native iOS terminal application that offers better performance than iSH. However, it also has limitations:

• No rsync support
• No SSH server functionality

Therefore, we need to use a computer as an intermediary.

Why Use a Linux Computer as Intermediary

Some filename formats supported by iPhone aren’t supported by Windows (such as filenames containing special characters). To avoid filename compatibility issues, we recommend using a Linux computer as intermediary.

If you only have a Windows computer, you can choose the non-extracted tar archive solution (see below).

Complete Step-by-Step Guide

Solution 1: Using Linux Computer as Intermediary (Extracted Storage)

Step 1: Open a-Shell on Source iPhone and Select Directory

pickFolder  # Select the WeChat archive directory to transfer

Step 2: Upload to Linux Computer

tar czf - ./wx | ssh user@ip "cd ~/upload && tar xzf -"

This command will:

1. Compress the ./wx directory into a tar.gz stream
2. Transfer via SSH to the computer
3. Extract in real-time on the computer

Step 3: Verify on Computer

# Check file count
find . -type f | wc -l

# Check total size
du -sh .

Step 4: Download to Target iPhone

In a-Shell on the new iPhone:

pickFolder  # Select target directory

Then execute the download command:

ssh -c aes128-ctr user@ip "cd ~/upload && tar czf - ." | tar xzf -

Using -c aes128-ctr encryption algorithm can improve transfer speed.

Solution 2: Non-Extracted Tar Archive (For Windows)

If you’re using a Windows computer or want to avoid filename compatibility issues, you can choose not to extract the tar on the computer.

Upload (From Source iPhone)

pickFolder  # Select directory to transfer
tar czf - . | ssh user@ip "cat > ~/wx_backup.tar.gz"

Download (To Target iPhone)

pickFolder  # Select target directory
ssh -c aes128-ctr user@ip "cat ~/wx_backup.tar.gz" | tar xzf -

This keeps the tar archive compressed on the computer and only extracts on the iPhone, completely avoiding Windows filename compatibility issues.

Monitoring Transfer Progress

Monitor progress on the computer (for Solution 1):

watch -n 3 'echo "Size: $(du -sh . 2>/dev/null | cut -f1)"; echo "Files: $(find . -type f 2>/dev/null | wc -l)"'

This refreshes every 3 seconds, showing current directory size and file count.

For Solution 2, monitor tar file size:

watch 'ls -lh ~/wx_backup.tar.gz'

Verifying File Count in Tar Archive

If using Solution 2 (non-extracted tar), you can count files without extracting:

# Count files in tar.gz
tar tzf ~/wx_backup.tar.gz | wc -l

# To count only files (excluding directories)
tar tzf ~/wx_backup.tar.gz | grep -v '/$' | wc -l

tar tzf lists archive contents without extracting, -t means list, -z means gzip compression, -f specifies file.

Windows Users Note: The above monitoring and verification commands are for Linux/macOS. Windows users can use AI (like ChatGPT, Claude) to convert these commands to PowerShell or Windows Command Prompt equivalents.

Summary

Solution	Advantages	Disadvantages
Solution 1 (Linux extract)	Can view/manage files on computer	Requires Linux environment
Solution 2 (Non-extracted tar)	Windows compatible, no filename issues	Cannot directly view files on computer

For transferring 10GB with 110K files, this SSH + tar streaming solution is much more efficient than file-by-file copying and more reliable than AirDrop.

Actual Test Speed

In a Wi-Fi LAN environment, transfer speeds can reach 100Mbps (~12.5MB/s). At this speed, 10GB of data takes approximately 13-15 minutes to transfer.

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