[wsl2] filesystem performance is much slower than wsl1 in /mnt

I decided to open this as a separate issue because although it's related to the generic issue of filesystem performance it's directly related to WSL 2 while the other issues are for WSL 1 and it's showing very conflicting results. * Your Windows build number: (Type `ver` at a Windows Command Prompt) Version 10.0.18917 Build 18917 * What you're doing and what's happening: I'm testing filesystem write speed in /mnt using dd command. Performing the following tests ### WSL2 root@LUCIANO-PC:/home/# dd if=/dev/zero of=/mnt/e/testfile bs=1M count=1000 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB, 1000 MiB) copied, 25.939 s, **40.4 MB/s** ### WSL1 root@LUCIANO-PC:/home/# dd if=/dev/zero of=/mnt/e/testfile bs=1M count=20000 20000+0 records in 20000+0 records out 20971520000 bytes (21 GB, 20 GiB) copied, 47.4897 s, **442 MB/s** On / it's actually the reverse. WSL2 is more than 2 times faster than WSL1. * What's wrong / what should be happening instead: I would expect the filesystem performance in /mnt to at least be on the same level but it's over 10 times slower. Another interesting fact is that if I mount the same drive as a cifs share I get 3x performance ### WSL 2 (cifs share) root@LUCIANO-PC:/mnt/sambae# dd if=/dev/zero of=/mnt/sambae/testfile bs=1M count=10000 10000+0 records in 10000+0 records out 10485760000 bytes (10 GB, 9.8 GiB) copied, 84.001 s, 125 MB/s ### An update of the current status because it's way too hidden in this thread. Late

Posted by ioweb-gr on Jun 19, 2019, 10:29 PM

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