Replacing my Linux VM with Hardware

2021-04-01T20:47

I've previously written about the Linux VM on my Mac. It's running in VirtualBox. It has tight integrations with the host to make it feel near native, but has a GNU tool-chain¹. I've been using this setup for about a year now but VirtualBox's problems are getting a bit old.

Sound has been a never-ending problem which I only use for cmus², my audio player. There was time that ran I cmus on the host and connected back from the VM, a path that went something like this: `host -> ssh to vm -> tmux -> ssh to host -> cmus`. That didn't feel right at all — it probably wasn't that bad, but still. Whenever I reconnect my laptop to my docking station (which includes an external sound card) the chance is high that the sound wont work anymore. I've resorted to some rather drastic measures like reloading the kernel module when I start cmus.

It also is annoying that I can't reliably run background tasks. So often I run a command, close my lid expecting it to continue. It's also annoying to leave the lid open and have the machine fall asleep and stop the task. I've been using Caffeine³ which is okay, but I'd rather avoid the problem entirely.

And for some reason VirtualBox takes more memory from the system than I allocate. Why? I don't know? It starts off fine, but after a couple of days it exactly doubles. Right now the VM is allocated 4GB and but it's using over 6GB. It's been up for a day. On my 16GB laptop, I can't really allocate more than about 4GB. Allocating 6GB will leave just 4GB for MacOS after it finishes growing. That's too little for Slack, Firefox and MacOS.

To overcome these issues I have started building a physical machine to replace it.

Last weekend I picked up a computer I had stashed at my Mums house for years. I remembered it being some low power Sempron, but it was actually a Phenom II X4 945. While it's awesome that it has four times the cores, it's also a 95W CPU. This concerned me a bit. My home office is actually a cupboard — a nice walk-in wardrobe with a window and all, but it is small and it heats up quickly.

Before I could use it, I needed to at least buy some RAM which had gone missing. I ordered 8GB of DDR3 memory, 2 Samsung 870 250GB SSDs and two fans to keep it cool.

It went together without any trouble. I installed Debian 10 with the SSDs configured in RAID 0. The machine doesn't support M.2 disks so I'm limited to SATA3's ~500MB/s. I fairly regularly AWK tens of GB of logs, so to me it's worth the extra risk of RAID 0 for twice the throughput. I did consider RAID 5 and I still might change my mind about that. A quick benchmark with dd showed I was writing at around 950MB/s and reading at 1100MB/s. I also put in a 1GB HDD to backup the SSDs and store large files that don't need fast access speeds.

After using it for an evening, my little cupboard warmed noticeably. I was expecting the idle power usage to be ~150W and thought about how I could reduce it. The next morning I measured the actual power draw from the wall. It was only 70W. Because I use this machine entirely through SSH, I removed the NVIDIA 220 GT graphics card. The machine still happily booted and now had an idle power consumption of 50W. When building it, I noticed that the motherboard had a serial header. I've ordered the header cable and a null-modem USB cable which I'll setup to access the console. That way, I'll only need to reconnect the graphics card if I must access to the BIOS or GRUB. That should be rare.

The ASUS motherboard prevented me from slowing down the new fans I bought. Since they were noisy at full speed and the machine is only generating 50W of heat, I disconnected them. Only the PSU fan provides airflow but the sensors show that it's working well enough.

The full hardware list is:

Asus M4A87TD/USB3

AMD Phenom(tm) II X4 945 Processor

G.Skill Ripjaws F3-12800CL9-4GBXL0 (2x4GB)

Samsung SSD 870 250GB (2)

WDC WD10EACS-00D 1TB (1)

Noctua NF-A8-PWM 80mm NF-A8 PWM Fan (2)

Vantec 450W PSU

Superflower case

I'm so glad I still have that case. I bought it second hand in about 2005 for maybe $150. I love that the motherboard is on a draw that you can slide out of the case to work on. I think that case needs a post of its own. It's that good.

¹ A MacOS/Linux Hybrid

² cmus

³ Caffeine

Some things that I'll be experimenting with soon are:

Roc Audio Streaming

Syncing data with Hazel

Console over ttyS0

Wake on Lan

Dynamic DNS with using Route 53 record sets

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