#POSIX ACL
Web vs. Worker — mkdir 0700 Disables Inherited ACL Permissions
One app runs as two users, with php-fpm handling web requests and a separate account running the queue. Even with default ACLs fully configured, they still cannot write to each other's directories. The cause is mkdir with mode 0700, which sets a mask that wipes out the effective ACL permissions, plus a deletion trap that requires permissions on the directory, not the file.
Rebuilding DirectAdmin Backups with NFS and POSIX ACL in Production
A record of rebuilding backups on a DirectAdmin server after migrating to a new machine — from FTP push that broke at three layers to an NFSv4 hard mount + POSIX ACL, with kernel-level lessons learned along the way.
Moving DA to Debian 12, Part 2 — Switching Storage to a ZFS Mirror
Replace the three storage layers of mdadm RAID1 + ext4 + qcow2 with a single layer of ZFS mirror + raw zvol while the old VM stays online, by degrading RAID to a single disk.