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Important notes

VM initialization

  • When you first run anylinuxfs to mount a drive, it will download the alpine Linux image from Docker hub and unpack it to your user profile (~/.anylinuxfs/alpine). Then it will spin up a VM so it can install dependencies and do the initial environment setup. After that, the Linux root filesystem will be reused for every mount operation. You can also run anylinuxfs init to download a fresh copy of alpine:latest and reinitialize the environment at any time.

Custom CA certificates

  • If you need to add custom CA certificates for the alpine VM to download packages, you can do so by adding them to a file in your user profile (~/.anylinuxfs/ca-certificates.crt). The CA certificates must be in newline-separated PEM blocks. These will be appended to the alpine image defaults during the first run of anylinuxfs, or when calling anylinuxfs init.

Permissions

  • It is needed to run mount commands with sudo otherwise we're not allowed direct access to /dev/disk* files. However, the virtual machine itself will in fact run under the regular user who invoked sudo in the first place (i.e. all unnecessary permissions are dropped after the disk is opened)

Memory requirements for LUKS

  • When you mount a LUKS-encrypted drive, the microVM requires at least 2.5 GiB RAM for cryptsetup to work properly. If your VM is configured with a lower amount of memory, you'll get a warning about it and the RAM configuration will be adjusted automatically. If you don't want to see the warning, set your default RAM to match this requirement (anylinuxfs config -r <size-in-MiB>)
  • Configured amount of RAM is the maximum that can be allocated. The actual amount of memory consumed by the VM can be lower.

NTFS

  • anylinuxfs provides two different NTFS drivers
    • the user-space FUSE-based ntfs-3g (better compatibility)
    • the more recent kernel-space ntfs3 (significantly better performance)
  • ntfs-3g is used by default
  • ntfs3 can be used by specifying -t ntfs3 option when mounting
  • Important things to keep in mind
    • ntfs3 cannot mount NTFS drives from Windows systems which were hibernated or which have Fast Startup enabled
    • ntfs-3g will fall back to read-only mount and issue a warning in this case
    • ntfs3 will generally refuse to mount a drive if it has any filesystem errors
    • using any unofficial tools like ntfsfix to clear dirty flag will not really fix those errors and can lead to further data corruption!
    • chkdsk on Windows is the recommended way to fix NTFS errors
    • some users also have good experience with chkntfs by Paragon (proprietary)
    • there are permission issues reported when using ntfs3 with Windows system drives
    • specifically, /Program Files some folders within /Users are read-only (see this reddit post for details)

To summarize

  • There are stories online about data corruption (or system freezes) caused by the ntfs3 driver.
  • They might or might not be caused by improper use of ntfsfix.
  • ntfs3 is included in the mainline Linux kernel so it is considered stable. It was contributed by Paragon Software in 2021.
  • If you trust it, want the best performance and you're OK with inconsistent permissions on Windows system drives, use ntfs3
  • Otherwise you're probably better of with the default and more established ntfs-3g