Revisiting the home data center architecture

If all goes well I will be adding one or two extremely powerful and new servers in the coming months.

Those servers use 2.5″ disks so the only question is how to implement large scale storage system. I have an old E6600 based server which would be perfectly fine if two 1Gbit connections were trunked together to get 2Gbit iSCSI connection.

2TB in 2.5″ form factor seems to be most cost effective, and prices for 3TB are beyond economical. So if one server could take 4 disks that would in mirrored configuration give 2TB of storage with some faster storage in form of SSD; left over from L2ARC and SLOG.

The old DL360 G3 would be dedicated to only work as firewall and traffic shaper and routing and switching would be moved to dedicated managed gigabit switches.

Also now all servers boot from NFS which has proven to be good, but problematic in case of failure in that NFS server, which has potential to either lock or bring down all the other servers. So NFS would be removed in favor SSD based mirrored ZFS root.

One question mark is my current networking setup which relies heavily on Linux, and which would need to be ported to managed switches. It shouldn’t be a problem, though, since it is technically all VLAN based with some bridges with more specific rules; so those would need to addressed somehow.

Also something like pfSense could be considered. But with firewall and router, if such system is used, I would like to move from i386 to 64bit architecture because currently there have been problems with not enough memory. HP ProLiant DL380 G5 might suit the purpose perfectly as a low cost server.

Quad gigabit PCIe network cards seem to be quite cheap so with three slots it would act as 12-port gigabit router. That would enable either the current Linux-based routing scheme or transition to something like BSD based pfSense. BSD has a reputation of being network oriented system and some studies have demonstrated that it performs extremely well as a router.

But one thing to remember with Linux/BSD based routers is to make absolutely certain that the driver support for network cards is perfect. Otherwise the stack will fall apart. Dedicated routing hardware works perfectly because it has been built to match perfectly with what it was built to be — router and nothing more.

So if the new QEMU/KVM hypervisor would set me back 400 €, disks perhaps 500 €, router 300 € and one or two additional small switches yet another 200 € and 1400VA UPS 250 € then the price tag woud be 1 550 € which isn’t too bad.

That cost would hopefully give me room for another 3 years at least and 2TB of storage and possibility to expand that storage to 14TB by using the router as FC based storage node by dropping 4 gigabit ports to accomodate for the FC card.

Serious home internet connectivity upgrade

The main connection will be upgraded from consumer grade 100M/10M to enterprise grade 100M/100M in near future.

This will affect the Tor service in positive way, such that as it now runs on my secondary 10M/10M best-effort line, it will be upgraded probably to some 70M/70M of which 50M/50M would be guaranteed and the rest best-effort.

Tor won’t still be running exit because that is too dangerous, but hopefully the relay will use all the bandwidth allocated to it.

Current Tor dedicated secondary line will either become another Tor relay or will stay idle as reserve line.

These two lines are from different providers so if one of them has problems in their networks the otherone should still work. They use same fibres so in case something there goes catastrophically wrong then there is nothing to be done.

But this would cost me 150 € a month so I still need to think about it. I can afford it but it is still quite a bit of money if there will be no proper usage for it. 100M/20M would be 100 € but that’s so small it makes no difference to my current 100M/10M.


Safety upgrade for home data center

Simply because if it goes up in flames or if the active cooling somehow malfunctions, and because it is a good practise to have fire extinguisher at around any type of serious setup and it gives a good impression.

There is hot aisle in my setup and it is constructed from sound proofing material found in office buildings, so that, too, ought to be fire resistant and give some additional protection against catastrophic PSU failure, which has the potential to spark because those are high current devices and there is a lot of capacitance in form of electrolytic capacitors and if, for example, one of those was to short, it would make not only an explosion but a visible one.

So I strongly encourage anyone with any sort of system to get one. And it is a good practise to have one at home, regardless of what you have or don’t have.

serveimage (86)

Next step would be to purchase carbon dioxide in a canister and hook it to smoke detecting system, to operate a valve when fire or gasses would be detected.

That would be an interesting project but you might also end up killing yourself if you have too much carbon dioxide and something was to go wrong. So it would possibly require secondary or even tertiary monitoring system to make sure that never happened.

But that being said, get one of these.

And these are not expensive devices by any means. Little 2kg was 19.90 € and it should last (best by) for at least couple of years.


Reusing some old equipment for ventilation improvements.

Two servers idle @ 500W in a small closet and semi-passive ventilation doesn’t do it so decided to hook one well-served 70W air moving apparatus to outlet.

Apartment has dedicated line out so it does not affect the neighbours.

Core 0: +48.0°C (high = +80.0°C, crit = +100.0°C)
Core 1: +50.0°C (high = +80.0°C, crit = +100.0°C)

70W tradeof for 5-10 °C lower ambient temperature, cooler components; longer age and quiter sound due to low RPM fans; perfectly affordable 70 Watts.

And this 70 Watts will prove to be important once the upgrade to two 120 Watt Quad-Core CPU is in place.

And if and when I get to run them at any considerable load with virtual machine plans ahead.

By the way, that device cost me maybe 60 € years ago, moves some 200 cubic meters of air per hour, has very smooth ball bearings and is still working perfectly after countless hours.