Unifi Gen2 PoE switch advice

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MickeyD

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#268143 2-Mar-2020 09:30

I need to replace my PoE switch which has died.

My dilemma is really around active vs passive cooling - my general impression is that passive cooling products are usually overly optimistic and likely to die sooner than actively cooled systems.

I've got a unifi setup at home, so keen to stick with their line of products.

I'm comparing the passively cooled USW-24-POE Gen 2 vs the USW-Pro-24-POE Gen 2. For my needs, the difference is no fan vs fan (and to a lesser degree power output). I'm pretty sure that 120W from the home model would be enough for my needs, however 22.5 dB fan noise from the pro would be fine if it'll help keep the system cooler.

It needs to power:

3x Unifi cameras
2x UAP-AC-pro access points
2x UAP-IW-HD access points
Yealink WP52 base station.

So, is anyone using the passively cooled USW-24-POE Gen 2? How hot does it get (ideally under a similar load), and what's the airflow like around your setup?

The pro has a max power output of 450w, vs 120w for the non-pro model. Is heat production likely to be the same if using the USW-Pro-24-POE Gen 2 for the same given load?

I'm leaning towards the pro model, but wonder if I'm over calling it.

The device will sit in a rack with approx 1" space above it (with a non-POE switch) and 2" below. The rack is in a cupboard which gets up to about 30-35 deg in summer. The cupboard door stays open to aid with airflow, and there's an extractor fan at the top of the cupboard to vent heat, but that fan is noisier than a jet engine so I'd prefer not to use it if I can avoid it.

richms

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#2430463 2-Mar-2020 21:14

Fan noise is in dBr, so basically totally misleading numbers there.

You are also getting the 10 gig uplink on the pro which the other does not have, and the fancy screen which will look nice if you also get the dream machine pro to use as a router when that is available here finally.

Richard rich.ms

fe31nz

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#2431520 2-Mar-2020 23:50

I have never used a POE switch, but as a general rule, fans are the earliest thing to die in most equipment unless you oil them at least annually. And not all fans can be oiled. When a fan fails, it often means the equipment will overheat and die within seconds or minutes. So fanless equipment, when properly designed and used with the specified ventilation room, is normally much longer lasting than equipment with a fan. Not all fans are the same, though. Big slowly rotating fans tend to last a long time, where small fast ones die early and are much louder also. And the bearing type matters a great deal. Ball bearings rule!

The rack mount form factor used in a lot of switches limits the size of the fans that can be used - they tend to be small noisy ones with low lifetime. So it pays to check on the fan type and quality before buying equipment with fans.

As an example, I have had both fan and fanless Nvidia video cards. All the fanless ones are still operational - they have lasted until they have had to be replaced for other reasons and would still work if installed again. Typically I have used them for 8+ years 24/7. One is still in use. The one Nvidia card I tried with a (tiny) fan failed within a couple of years of 24/7 operation.

As a counter example, last year I retired my old 16 port gigabit switch in favour of a 24 port managed commercial grade switch. It was a rack mount style one, and was cooled by three tiny fans on the right hand side. They were quite noisy, and got a bit noisier over its lifetime, but they were all still running fine last time I powered it up. So I presume that they were quality fans. It had been running for 7+ years 24/7 at retirement.

MickeyD

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#2431689 3-Mar-2020 11:27

Thanks for the replies.

@fe31nz Thanks for the insight regarding fanless products - it's interesting to get a counter opinion and I understand the concept that no moving parts means less mechanical reason to break. I'm unsure how applicable experience with a fanless graphics card is in this situation however, as those systems invariably still have a system fan to move air past the heat sink, and usually aren't as cramped as a 1 unit server.

This will be my third rackmount PoE switch. I presume that it was heat that killed my first two. I've never had a fan fail, although do take care to ensure they're working properly and perform basic maintenance like making sure they don't get clogged up with dust. Fan quality and airflow design both matter, both from air movement and noise perspective. In systems I've built previously I tend to use large noctua fans for that reason. While I can replace the fans with higher quality ones in the switch (voiding the warranty), I can't change them for something larger.

The early Unifi POE switches were really hot and noisy. They have been progressively improving since that time, I'm just not sure if they've improved enough to warrant no fan in the location where my rack is situated.

So taking advice from @richms I'll try out the pro model. I've started getting some 10G gear so I'll consider it future proofing.

billgates

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#2432142 3-Mar-2020 21:39

Have you considered other brands PoE switches? FS.com have a good variety and pricing is very good. For same price as Ubiquiti 24 port USW-Pro you can get 48 port version of FS.com variant.

https://www.fs.com/au/c/1g-10g-switches-3256?yes=21606

Do whatever you want to do man.