Curious Case of Maintaining Sufficient Free Space with ZFS

Sun, 10 Jul 2022 12:25:59 +0300

TLDR: ZFS free-space reporting is a lagging indicator.

Background

I use Proxmox VM server backed by a ZFS array of hard drives for various personal infrastructure. I also have security cameras that upload motion-triggered videos to my server (via FTP!).

Problem Description

I would like to use 90% of my available space for most-recent security videos.

Recipe:

Create a dedicated ZFS volume
Setup ZFS quota
Run a cronjob to free space faster than it gets consumed by video uploads.

I set out to find a decent disk-freeing solution. I eventually settled on a python free-disk. (Most of these utils were written in bash, didn’t want to disk having to grasp & modify write-only code).

Zfs on Taras' Blog on AI, Perf, Hacks

Curious Case of Maintaining Sufficient Free Space with ZFS

Background

Problem Description