WSL Configuration¶

Windows Subsystem for Linux can be optimized and tuned using a configuration file located at C:\Users\.wslconfig. In the sections below we discuss some configuration that can be tuned to optimize Finch. For a full list of .wslconfig configuration options see the Microsoft documentation here.

Warning

The configuration changes which modify your .wslconfig file will apply to ALL WSL 2 distributions.

Limiting CPU and memory usage¶

For users who want to replicate Finch's finch.yaml memory and cpu can instead use similar options in their .wslconfig file, like so:

[wsl2]

# Limits VM memory to use no more than 4 GB.
# This can be set as whole numbers using GB or MB
memory=4GB 

# Sets the VM to use two virtual processors
processors=2

Reclaiming memory automatically¶

In addition to setting max memory limits, user's can also specify to clean up WSL cached memory automatically. With this setting unset, cached memory remains allocated by the WSL 2 VM until shutdown.

[experimental]
# Automatically releases cached memory after detecting idle CPU usage.
# Set to gradual for slow release, and dropcache for instant
# release of cached memory.
autoMemoryReclaim=dropcache

Steps to Disable C Drive Auto-Mount¶

Step 1: Disable C Drive Auto-Mount in WSL Configuration

Log in to the Finch VM and disable the C drive auto-mount in the WSL configuration:

PS C:\Users\Administrator> wsl -d lima-finch
[root@EC2AMAZ-R56AQRB Desktop] cat /etc/wsl.conf
[boot]
systemd=true

# Disable auto-mount
[automount]
enabled=false

Step 2: Modify fstab for mounting C Drive in read-only

Edit the fstab file to add entries for mounting the C drive in read-only mode. Some Finch commands require read-write access to C:/Users/Administrator, so we'll need to mount that directory in RW mode.

[root@EC2AMAZ-R56AQRB Administrator] vi /etc/fstab
C:/ /mnt/c drvfs ro 0 0
C:/Users/Administrator /mnt/c/Users/Administrator drvfs rw 0 0
C:/source-dir-path /mnt/mount-dir-path drvfs perms 0 0 # Can add more dirs which requires RW access if needed

Step 3: Exit the VM and Restart Finch

To apply your changes, exit the VM and restart Finch:

PS C:\> wsl --shutdown 
PS C:\> finch vm status
Stopped
PS C:\> finch vm start

Finch on Windows does not make any claims or guarantees regarding VM-level isolation, so consider the machine as the security boundary.