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Slow Copying with Captive NTFS

2006, September 8 - 10:57am — vyvy

11-Sep-06 Update: I've done another experiment with a slightly different setup.

Last night, I copied a few files from an ext3 partition to an NTFS partition by using the Captive NTFS module (version 1.1.7). It's the latest version as of this writing. It's expected to be slow mainly due to the emulation. But how slow it is?

I copied a total of 10 files occupying 459,447,144 bytes. I made a rough measurement with the following commands:

/usr/bin/time -v cp files_in_ext3 folder_in_ntfs
/usr/bin/time -v sync

The command sync is there to force all pending write operations to be committed. I also measured the time required by using the same set of commands except that the files were copied to the same ext3 partition (and thus the linux's native ext3 module was used). The table below summarizes what the elapsed time required for each operation:

Command	Time Elapsed (seconds)
Command	Copying to NTFS	Copying to Ext3
`cp`	826.15	1.50
`sync`	25.89	2.17

You may notice that the sync operation didn't take much time, and the time taken to sync for ext3 is more than that for NTFS. I'm not exactly sure why it is so and don't bother much to find out now. (Tell me if you know the exact cause.) After all, the cp command dominates the performance and it is thus sufficient to make our calculation based on the time it takes. From the figures, copying with the Captive NTFS is about 30 times slower than that with the native ext3 module.

Anyway, the measurement is very rough. But it does give you some ideas of the time required if you use Captive NTFS. The slower performance is okay for me as the driver really works reliably.