# /var/log full — plexstreams polling a dead address

**Date:** 2026-11-03 (silent since 2026-10-28)
**Severity:** P2
**Status:** Resolved

## Symptoms

`/var/log` on Unraid at **100% of its 128 MB tmpfs**. Any process trying to log
failed with `errno=28 No space left on device`. Found by accident while
installing an unrelated script that tried to write a log file there.

```
tmpfs  128M  128M  0  100%  /var/log
  48M  phplog
  37M  syslog
  31M  tailscale.log
 6.6M  tailscale-utils.log
```

## Timeline

| Time | Event |
|------|-------|
| 2026-10-10 16:21 | First `phplog` entry. Plex had moved to host networking; plexstreams kept its old address |
| 2026-10-10 → 10-28 | 99,926 failed polls, three PHP warnings each, ~every 15 s |
| 2026-10-28 07:12 | Last entry written — **not** because errors stopped, but because the filesystem filled |
| 2026-10-28 → 11-03 | Logging silently dead across the box for six days |
| 2026-11-03 22:20 | Found, diagnosed, fixed |

## Root Cause

The **plexstreams** plugin was configured with
`HOST="http://192.168.31.2:32400"`. That address is on the macvlan shim subnet —
the same dead `192.168.31.0/24` range created in `/boot/config/go` for a Pi-hole
that AdGuard replaced. Nothing answers there.

Plex itself runs with **host** networking and answers on `192.168.10.20:32400`
(HTTP 200). plexstreams was never updated when Plex moved.

Each failed poll returned an empty body, so `simplexml_load_string()` failed and
logged three warnings:

```
PHP Warning: simplexml_load_string(): Entity: line 1: parser error : Document is empty
  in /usr/local/emhttp/plugins/plexstreams/includes/common.php on line 180
```

299,778 of 299,934 lines — **99.95% of the file** — were those three warnings.

## Fix

1. `HOST` and `hostbox` in `/boot/config/plugins/plexstreams/plexstreams.cfg`
   repointed to `http://192.168.10.20:32400`, with `ALIAS-192_168_10_20="unraid"`
   added so the UI still shows the right name. Backup at `plexstreams.cfg.bak-*`.
2. `phplog`, `tailscale.log` and `tailscale-utils.log` **truncated**, not
   deleted — deleting a log a process holds open frees no space until that
   process restarts, and the writer keeps appending to an unlinked inode.
   `syslog` was left intact as the only remaining record of the period.

Result: `/var/log` 100% → 35%. Verified over 60 s (four poll cycles) that
`phplog` stayed at 0 bytes with no new plexstreams warnings.

## Open items found in the same log

- **`appdata.backup` exhausted PHP's 256 MB limit 18 times**
  (`Allowed memory size of 268435456 bytes exhausted`). Appdata backups may be
  failing. Not investigated.
- **`zfs.master`**: `Trying to access array offset on null` ×130 — cosmetic
  plugin bug.

## Lessons

- The six-day gap is the real damage: a full `/var/log` is silent. Nothing
  alerts on it, and `syslog` for 2026-10-28 to 11-03 is incomplete.
- Worth a periodic check on `/var/log` usage; `go` already installs an rsyslog
  noise filter, so log volume has been a problem here before.
- The dead `192.168.31.0/24` shim keeps surfacing. It was also the pointless
  route Unraid's Tailscale node used to advertise, removed the same day. The
  shim itself is still created in `go` for a Pi-hole that no longer exists.