New comment by mobinmob on void-packages repository

https://github.com/void-linux/void-packages/pull/28783#issuecomment-779946896

Comment:
> Does that make `/usr/lib/66` receive writes all the time? Maybe `/etc` is a better place? That said, `/var/lib` even holds the random seed from runit, so I'm not sure how likely it is to be a separate mount point.

Not all the time, no :) Regular writes will happen in /run/66 (tmpfs) and /var/log/ for the services after stage1/boot tree - early boot log is saved under /run/66. The contents of system dir do not change all the time, only on user configuration changes.
User configuration is already done in /etc/66. I can use the same for system-dir if it is a better option - it will certainly work. 
The change is prompted by a failure to boot a voidlinux system installed via voidvault, which uses btrfs subvolumes for some /var subdirectories.