Re: Reason why "nocache" option is not displayed in "mount"?

From: Christos Chatzaras <chris_at_cretaforce.gr>
Date: Thu, 07 Mar 2024 13:59:48 UTC
> what is the reason why "nocache" is not displayed in the output of "mount" for nullfs options?
> 
> # grep packages /etc/fstab.commit_leidinger_net
> /shared/ports/packages          /space/jails/commit.leidinger.net/shared/ports/packages         nullfs  rw,noatime,nocache      0 0
> 
> # mount | grep commit | grep packages
> /shared/ports/packages on /space/jails/commit.leidinger.net/shared/ports/packages (nullfs, local, noatime, noexec, nosuid, nfsv4acls)
> 
> Context: I wanted to check if poudriere is mounting with or without "nocache", and instead of reading the source I wanted to do it more quickly by looking at the mount options.

In my setup, I mount the /home directory using nullfs with the nocache option to facilitate access for certain jails. The primary reason for employing nocache is due to the implementation of ZFS quotas on the main system, which do not accurately reflect changes in file usage by users within the jail unless nocache is used. When files are added or removed by a user within jail, their disk usage wasn't properly updated on the main system until I started using nocache. Based on this experience, I'm confident that applying nocache works as expected in your scenario as well.