Microsoft Still Working To Squeeze More I/O Performance Out Of WSL / Bash For Windows

Written by Michael Larabel in Microsoft on 9 August 2018 at 08:05 PM EDT. 27 Comments
Windows Subsystem for Linux, a.k.a. WSL or "Bash for Windows", has been an interesting creature out of Microsoft for running Linux binaries on Windows 10 and more recently Windows Server. In our benchmarks WSL has generally been quite performant but the area where it struggles is I/O / storage performance.

The I/O performance in WSL has always struggled due to having to deal with Linux file operations and tracking all of the associated meta-data while backing it by the Windows NTFS file-system. That overhead has been very significant in slowing down programs/services/benchmarks requiring frequent reads/writes while in CPU/system workloads WSL is very competitive to bare metal Windows 10 performance or that of various Linux distributions, as shown in different Phoronix articles.

Microsoft has said they have developers working on improving the WSL I/O performance and that was reaffirmed today. Microsoft's Rich Turner reaffirmed on the GitHub issue tracker, "Disk IO perf remains VERY HIGH up our list of improvements we're actively working on. Once we have an actionable solution to this issue, you'll barely be able to NOT hear about it...We'll also do our best to update issues/threads like this one when we do have something positive to report."

Microsoft hasn't said when these I/O improvements may arrive, but we can hope it will happen in time for the next Windows 10 installment. The Windows 10 "Redstone 5" update is expected for release in October, so hopefully we will find out more on WSL improvements prior to that next milestone.
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Michael Larabel

Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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