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I have about 15gb of data that I wish to copy from my NTFS external harddrive connected via USB to the ext4 partition of my harddrive. While copying from my laptop's NTFS harddrive the rate was about 20mb/s. In the opposite direction, however, the rate is about 3mb/s. Am I missing something important or is there something wrong?

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As far as I know the Linux NTFS support is not very performant, especially when writing. On older, slower machines you sometimes even notice that your whole machine gets slower because of the CPU usage. I don't know if those problems still persist and even back then I was missing backround knowledge so I'm not writing this as an answer. Reading NTFS is kind of allright, that's why you experience the effect only in one direction. – André Stannek Jan 7 '13 at 1:13
up vote 3 down vote accepted

I just tried the option big_writes with NTFS USB drive, helps quite a bit. Write speed went from 2 MB/s to 28 MB/s and I checked for data corruption after the copy, data was absolutely fine. Following is the command:

sudo mount -o big_writes /dev/sde1 /media/tmp
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There are several issues that may affect write performance and explain what you're experiencing. Without more technical details about your machine I can't tell you which of these are really relevant, but the usual suspects are:

  • As stonedsquirrel pointed out in comments, write performance depends on filesystem. Under Linux, copying to an ext4 partition is expected to be faster copying to an NTFS one. ext4 is managed by a kernel driver, and it's highly optmized since it's the default filesystem in most Linux distribuitions, while NTFS (usually NTFS-3G from Tuxera) is a driver that runs in user-space, so it is much slower.

  • NTFS suffer a lot from fragmentation, and a heavily fragmented partition may have slower write performance.

  • Laptop's hardrives are optimized for lower power consumption, while desktop harddrives usually aim for performance. They usually run at 5400rpm (or lower), in comparison of 7200 from desktop HDDs. Other power-saving features may also trade in performance for longer battery life.

That said, both 20mb/s (for copying to an ext4, desktop hdd) and 3mb/s (for an ntfs, laptop hdd) seem quite normal

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