# PDR 001: Separate macOS work from persistent Linux services

- HTML version: https://robbiepalmer.me/projects/homelab/pdrs/001-separate-macos-work-from-persistent-linux-services
- Project: Home Lab
- Status: Proposed
- Opened: 2026-10-31

## Context

The Mac mini has 8 GB of memory and carries several unrelated jobs. It provides
macOS and iOS development, owns the 10 TB photo and media disk, and runs
Jellyfin, media automation, monitoring, VPN-dependent services, and coding
tools. Repeated full-memory conditions have caused complete host reboots.
Moving development work to the 64 GB Vector has reduced pressure, but it has
also made room for more development rather than eliminating demand.

The retired Asus desktop has 16 GB of memory, but its noise, size, old CPU, and
maintenance requirements make it a poor always-on companion. A small NixOS
computer could provide more memory and a quieter home for Linux-native
services while preserving the Mac for work that requires macOS.

The media services cannot be divided only by process name. Jellyfin, Sonarr,
Radarr, qBittorrent, photo export, and the 10 TB disk share storage paths and
failure modes. Splitting them across an unreliable upstairs Wi-Fi mount could
replace memory pressure with storage and network failures.

## Proposed decision

Add a quiet, small, always-on NixOS companion to move persistent Linux services
out of the Mac's constrained memory. The observed reboots already establish the
need. Measurements will size the new host and identify the services to move.

The companion should support at least 32 GB of memory, or allow a later upgrade
to that capacity. It does not need a discrete GPU or legacy CUDA support. Its
purchase must account for fan noise, Linux support, wired networking, storage
attachment, power recovery, and the physical location of every cable and disk.

Use it to move a cohesive set of Linux-native services rather than scattering
one storage workflow across unreliable links. Treat Jellyfin, media automation,
VPN routing, and the 10 TB disk as one placement decision. They may remain on
the Mac, or move together behind a reliable local storage boundary. Keep the
Mac as the macOS and iOS development machine and retain services that genuinely
depend on macOS.

Do not buy the companion merely to replace the retired desktop. Its capacity
and service placement must address the observed Mac pressure without creating
a fragile storage path.

## Consequences

A companion could stop Linux containers from competing with Xcode and macOS in
8 GB of memory. NixOS would also give its persistent services the same reviewed
and repeatable host configuration used by the Vector.

It would add another machine, operating system, power supply, backup boundary,
and purchase. Moving the media disk away from the Mac may also change the Ente
photo-export path. Keeping the disk on the Mac while moving the services may
create a network dependency that is worse than the memory problem.

The proposal therefore does not select hardware or move a service yet. A later
architecture decision must define the host and storage boundary after current
resource use and the physical network path are measured.

## Evaluation

Before accepting this proposal, record Mac memory pressure, swap, container
memory, and reboot diagnostics during normal media use. Use that evidence to
size the companion and choose which services move. Compare keeping the
storage-coupled services on the Mac with moving the complete group and disk to
the companion. After migration, normal media and macOS development use should
no longer exhaust memory or reboot the Mac.

## Related records

- Project: [Home Lab](https://robbiepalmer.me/projects/homelab.md)
- Informed by ADR: [ADR 008: Jellyfin media server](https://robbiepalmer.me/projects/homelab/adrs/008-jellyfin.md)
- Informed by ADR: [ADR 013: Automated media acquisition](https://robbiepalmer.me/projects/homelab/adrs/013-media-automation-arr-stack.md)
- Informed by ADR: [ADR 020: K3s for declarative homelab workloads](https://robbiepalmer.me/projects/homelab/adrs/020-k3s-declarative-workloads.md)
- Informed by ADR: [ADR 025: Graphical NixOS development workstation on the Vector laptop](https://robbiepalmer.me/projects/homelab/adrs/025-graphical-nixos-development-workstation.md)

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