We took a typical USB 3.1 thumb drive and performed three types of test. One was Sysbench with its fileio mode, which we used for synchronous reads and writes. It’s a synthetic test, but it does stress a filesystem far more than most manual file operations. Second was the Postmark read test (100,000 transactions), while the third was the dataset test, which involved unpacking a Linux kernel tarball on to the drive.
The results turned out to be interesting and varied between Sysbench, Postmark and the dataset unpacking. The more strenuous Sysbench test revealed that Ext4 was the fastest filesystem in terms of simultaneous read/write operations that involved large files already on the drive. However, when it came to a more dense flow of thousands of tiny files, XFS was the best according to both Postmark and the dataset test. Btrfs seemed to reside in the mid-range, with fairly good results, although we doubt whether there’s any sense in using the snapshot feature on flash storage – but who knows? Btrfs showed very balanced results anyway. Reiser5 ran rather well in all tests, even outperforming Ext4 in the dataset unpack test.