Keeping this for reference. I wanted to mount a VMDK disk on Linux, and be able to access its Alternate Data Streams (ADS). ADS are useful in the context of security for malware analysis and forensics purposes.

Mounting a VMDK Image With qemu Without ADS

I figured this out with these articles:

• https://stackoverflow.com/questions/22327728/mounting-vmdk-disk-image/30201153

• https://unix.stackexchange.com/questions/509973/mount-ext4-disk-cannot-mount-dev-sdc-read-only

sudo apt install qemu-tools
sudo modprobe nbd
sudo qemu-nbd -r -c /dev/nbd0 /path/to/whatever.vmdk
fdisk -l /dev/nbd0 # List partitions. You may want to mount something different than nbd0p1.
mount -o ro,noload /dev/nbd0p1 /mnt
...do work...
umount /mnt
sudo qemu-nbd -d /dev/nbd0

Accessing Alternate Data Streams

To access Alternate Data Streams and other NTFS from Linux: https://medium.com/@stdout_/accessing-ntfs-extended-attributes-from-linux-f79552947981

apt install attr
mount -t ntfs -o ro,streams_interface=windows /dev/nbd0p1 /mnt
getfattr -Rn ntfs.streams.list /mnt