Quanta LB6M (10GbE) -- Discussion

TheBloke

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Any chance those pics have been posted yet? I have fans in need of replacing :)
EDIT: I realised too late you were talking about PSU fan replacement, and already read posts I was going to add :)

I'll leave the following as a summary for newcomers regarding normal fan replacement and some links to fan mods.

To do a like-for-like replacement of a fan is super easy. The entire fan tray simply unscrews in the same way as a PSU does - two thumb-screws at the back, then pull it out:



Each fan is then held in with two diagonally-opposite screws into the back plate of the fan tray.

I've not yet replaced one myself, but one of mine is intermittently failing so I might do soon. The 4-pin connector is a different wiring to standard, so this needs to be checked for (see below.)

Here's a close-up of a fan:



By AVC, model number DB04028B12U. I can see a few on eBay - there's some cheap ones from China, but they're only 3-pin. But apparently the same fan is used in an HP ProLiant model, and there's some of those - albeit rather expensive.

Best of all is to put in one or more quieter fans, as others have done. Again, be aware that the 4-pin wiring is different to a normal fan, potentially requiring swapping pins on the connectors.

Here's a post from a guy who's done a single-12cm-on-the-top mod.

And here's Sleyk's mega-post on doing a fan mod, including lots of photos and discussion of the different 4-pin wiring.
 
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Ryan Anstey

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EDIT: I realised too late you were talking about PSU fan replacement, and already read posts I was going to add :)
Thanks! I appreciate the effort to help. Any idea how dangerous the PSU fan replacement job is? Opening a PSU in general sounds scary... hoping this one is just unplug fans, do a tiny mod to the new ones and plug them in. (My new fans just arrived from Amazon.)
 

TheBloke

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Thanks! I appreciate the effort to help. Any idea how dangerous the PSU fan replacement job is? Opening a PSU in general sounds scary... hoping this one is just unplug fans, do a tiny mod to the new ones and plug them in. (My new fans just arrived from Amazon.)
I haven't opened these PSUs before, but I have opened other PSUs before and they're not really that different to opening anything else. A little cramped maybe.

If the fan screws in and has a standard 3 or 4-pin fan connector, I can't see why it would be all that hard. But as I say, I've not opened it so I don't speak from specific experience.

If it were me I'd certainly open it up and if it seemed straightforward, proceed. Only if it seemed like I was going to have to do a custom job - drilling holes etc - would I pause.

Of course, if you have dual PSUs as I have, that gives you some insurance. As long as you can be sure you're not doing anything dangerous, it's probably worth a go.

I think I've seen @Sleyk around on the forum in the last days though, so he may well pop up soon to give more specific instructions. Always nice to do it after someone else has already been the guinea pig :)
 

TheBloke

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OK @Ryan Anstey I've just been your guinea pig. It all seems very easy mechanically, at least as long as your fans are identical size, are 3-pin, and are the SAME 3-pin. But the latter bit may not be true - more details at the end.
  1. Undo the six screws around the sides of the top panel (at the top of the left/right edges)
  2. Undo all the screws you see on the top panel
  3. Undo another 2 screws at the back end of the PSU, where the connector is, underneath - you can see the top panel wraps around to be held here at the bottom as well.
  4. Remove the top cover and the paper cover underneath:
  5. Now unscrew one fan from the PSU: each is held in a metal bracket, and the bracket is secured to the case via two screws: one to the outside of the case (look at the side of the case nearest to that fan), and another down into the base of the case, adjacent to the motherboard.
  6. You can now unplug the 3-pin connector, unscrew the fan from its metal bracket, and put in the replacement.
  7. Reverse the above steps to re-attach.
Unfortunately it is not possible to test this outside of the switch, with the case off. I just tried, by applying power when the PSU was out of the switch. The PSU light comes on, but nothing powers up because nothing is found on the connector.

So you'll have to put it all back together and test it inside the switch.

Before changing any fan you need to check if your new fan has its 3-pin fan connector wired differently. The fan in my PSU is AFB0412VHB, The datasheet is here. This indicates that red = +12V, black = ground, and blue = speed measurement. That's fine. But it appears the ordering on the 3-pin connector is perhaps not standard, or at least this can differ. And the ordering shown on page 6 of that spec doesn't match the ordering I see on the real fan in the PSU.

Checking the connector on this Delta fan in my PSU, I see that the order of the wires when looking at the side of the connector that has the notches is: Red, Black, Blue. I then took a random 3-pin fan out of my collection, and looking at this connector the same way, it was Yellow, Red, Black. Yellow will be the same purpose as Blue, the colour change is fine. But the connector appears to be wired completely differently:



On the left is the original PSU fan connector, on the right the one from a random 3-pin fan from my Box Of Fans. I double checked the data sheet for the other fan, a Sunon, and confirmed that as expected red = +12 and black = ground, so everything is definitely in a different order.

And I checked another couple of fans in my box, and they match the Sunon. So it's clearly the PSU fan that's different.

Therefore you should definitely expect yours to be wired differently, unless you bought the exact same model - and even then, check, as the datasheet for the Delta fan in my PSU seemed to indicate a different wiring than what's actually in the connector. So they may be standard Delta AFB0412VHB fans but with custom connectors.

It may be possible to simply pull the wires and pins out of the connector and push them back in another order - though sometimes they don't stay tight after that.

If not, you can buy 3-pin connectors and their pins, cut the connector off your new fan and then solder the new pins on and push them into the new connector in the right order. I've never done it with these fan connectors, but have with many other kinds of 2 and 3-pin connectors. Are you comfortable using a soldering iron?
 
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mrsonicblue

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Jan 20, 2018
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What I ended up doing with the PSU noise is to keep the original fans, but add an inline resistor to slow them down somewhat. If you know what you're doing, it would cost less than a dollar for a resistor. If you're lazy, like me, you can buy a pre-made cable that you insert between the fan and the PSU. I used the Noctua NA-SRC10. You can get them in packs of three for about $8 total. They reduce the noise CONSIDERABLY.

That said, I have no idea if this will eventually damage the PSU. As someone above pointed out, there are two PSUs. I'm willing going to run with it and if it ever burns up, I can try something else with the second PSU. I'm not pushing huge amounts of data, so hopefully the heat is manageable.
 
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TheBloke

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What I ended up doing with the PSU noise is to keep the original fans, but add an inline resistor to slow them down somewhat. If you know what you're doing, it would cost less than a dollar for a resistor. If you're lazy, like me, you can buy a pre-made cable that you insert between the fan and the PSU. I used the Noctua NA-SRC10. You can get them in packs of three for about $8 total. They reduce the noise CONSIDERABLY.

That said, I have no idea if this will eventually damage the PSU. As someone above pointed out, there are two PSUs. I'm willing going to run with it and if it ever burns up, I can try something else with the second PSU. I'm not pushing huge amounts of data, so hopefully the heat is manageable.
Yeah that's a good idea. I've used those cables in desktops and servers before. A worry is that there's no temperature monitoring of the PSU - I can't see any option in the switch OS, either the original Quanta or the newly-flashable Brocade - that monitors the PSU. So there'd be no way to see if temperature is building up. However, one would assume it has over-temperature protection, so as long as one is OK with it potentially shutting down the PSU and switch without warning, it's likely a risk worth taking. As you say, given many of us have two PSUs and are using them at home, it's probably no big deal. The cooling is designed so as to be able to always cool the PSU when at full, sustained power consumption, in a hot DC. As you say, at home we're unlikely to reach that - at least as long as the switch is not stuck in an un-ventilated cupboard or something :)

However, personally I'm thinking of doing a double 12cm fan mod: remove the 3x main switch fans and replace with a single 12cm fan mounted on the top panel above the processor area, and then cut a hole in the lid of one PSU and mount a second 12cm fan in the panel above it, so it now vents straight up. I never plan to run with dual active PSUs, so I only need to provide ventilation for one fan bay, and only mutilate one PSU.

A couple of 12cm fans at up to 2000 RPM each will be more or less silent, certainly compared to all my other server gear.
 
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TheBloke

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What I ended up doing with the PSU noise is to keep the original fans, but add an inline resistor to slow them down somewhat. If you know what you're doing, it would cost less than a dollar for a resistor. If you're lazy, like me, you can buy a pre-made cable that you insert between the fan and the PSU. I used the Noctua NA-SRC10. You can get them in packs of three for about $8 total. They reduce the noise CONSIDERABLY.
Hum.. I just had a thought: if you used a standard off-the-shelf fan speed cable, did you come across problems with the different wiring of the fan connector? The fan speed cable will put a resistor on a certain pin, and if the wiring is different, it could end up in a place where it won't work.

Though actually, it appears on my differently-wired fan that Ground is where +12 normally is. So if your cable has the resistor on the +12 line, then with the different connector it would end up on the Ground line. Which would still work. However, if it had the resistor on ground, it would end up on the blue/fan speed wire, which wouldn't slow the fan down and would presumably break the fan speed monitoring.

So either your fan isn't wired differently, as mine appears to be, or else I suppose the resistor must be on +12 and that got swapped to Ground which still works? My electronics knowledge is shamefully limited, but I do know that in a simple circuit, a resistor works the same way whether it's on the ground wire or +12v. Either way it will limit the current of the overall circuit.

So yeah I suppose it's most likely that.
 
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mrsonicblue

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Hum.. I just had a thought: if you used a standard off-the-shelf fan speed cable, did you come across problems with the different wiring of the fan connector? The fan speed cable will put a resistor on a certain pin, and if the wiring is different, it could end up in a place where it won't work.
I added the resistor a few weeks ago and didn’t think to check the wiring. The fans are definitely still spinning, but slower. I’m attaching the only picture I took of the fan, in case it helps.
 

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Ryan Anstey

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OK @Ryan Anstey I've just been your guinea pig.
Haha, I didn't seem to get notified of your post (or we both did this at the same time yesterday) so I just went at it cause the noise was getting to me. I don't usually work with hardware that much, so my goal was to just touch nothing and not die, lol.

A few days ago I did the main fans, that was easy (3x Noctua NF-A4x20 FLX):



The PSU (Delta DPSN-300DB (for the Google keywords)):

I used 2x Noctua NF-A4x10.



I used the rubber "screws" because the original screws nor the ones that came with the Noctua's didn't fit. I needed small needle-nose pliers to get them through.



I used the 3-to-2 pin adapter that came with the Noctua's and then matched the colors that were connected previously:



Everything is super silent now!
 

TheBloke

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Good stuff @Ryan Anstey . Those fans look really nice - but damn are they expensive over here. To buy three of the 20mm and two of the 10mm would cost me at least £75 (CAD$130). That's the same as I paid for my 48-port Gigabit LB4M switch! :D

I see that the Noctua fans have some kind of modular cable thing, so it can work with any pin combination? That's a nice feature - I can see why they cost a bit more.

Personally if I do any mod I think I'll just do a couple of 12cm fans on top, which I already have plenty of. But the noise issue is hopefully only temporary - before too long I hope to be able to move all my gear into my garage. Just need to work out cabling through the garden, as the garage isn't attached to the house.

Anyway glad you're happy with your mod!

PS. how are your switch temperatures with the 3 x 20mm Noctua's? Do you know what they were before you did the swap?
 

TheBloke

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Damn you, Ryan, now I'm wondering if I do need to spend silly money on quiet fans :p :)

If I can find a suitable replacement for the three fans in my server, then that would be interesting. There's not much point silencing the switch while the server still sounds like a (muffled) jet engine.

The server fans are 3 x 80mm, and Noctua do have 80mm options, including PWM. But theirs are only 55 m^3/h, running at up to 2200 RPM. My current fans run at up to 5700 RPM, providing 136 m^3/h. That's quite a shortfall. Then again, the fans don't usually exceed 4000 RPM. But it's still going to be quite a bit lower airflow from the Noctuas, so I'll have to try and work out if that can be enough cooling. I am running pretty cool at the moment so I have a little leeway to increase temps.

For the switch, I just noticed that Noctua have a 200mm fan. It's pretty expensive, although I guess only double the price of one of their 40mm fans.

I'm wondering if one single 20cm fan mounted on the top of the Quanta could server as cooling for the main switch and one PSU.

It only runs at 800rpm, but that provides 150m^3/h of air, which is 15 times higher than a 40mm fan, 5 times more than three of them. And it should be quiet enough to be inaudible.

That'd still require massacring the case, but work out a lot cheaper - and perhaps even quieter - than buying five individual 40mm fans for the switch and PSU.

Although a worry is whether the PSU will even start up without any fan detected. It might refuse to for safety reasons. Then again yours works fine when connected to a 2-pin fan, so maybe it doesn't care as long as temps remain low. Or the Noctua wire does something to fool the third pin into thinking a fan is there, which I could emulate with a custom wire.

EDIT: Well, I'm not one to stop myself buying things. Ordered 3 x 80mm fans, 2 x 60mm, 1 x 120mm and 1 x 200mm. Who was it who said this was a silly amount to spend on fans? Can't remember :)

Only part of the purchase pertinent to this thread is the 200mm, which I shall attempt to mod into the switch as combined cooling for the motherboard and PSU. I shall report back in due course :) I may not need all the other fans for my server, so I might end up putting two fans into the switch if one provides incapable of properly cooling everything. My main concern is that there's no easy way to monitor the temperature of the PSU. But hopefully it shuts down well before damage can be done.
 
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charlie

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Hi,

Is LB6M capable to be a "core" switch in small soho network (with 4 48 port gigabit switch). Including routing and OSPF to the uplink? (both ipv4 and ipv6)? Anybody using its for this porpuse?

(especially with this new brocade firmware)
 

segfault

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I use it that way but I don’t do any ipv6. It’s my core with two other switches as the edge (ex4200 and 3750x).


Sent from my iPhone using Tapatalk
 

TheBloke

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The new Brocade firmware is great and highly recommended to flash to. Yes it has OSPF and other routing protocols for ipv4. But no routing for ipv6 - a limitation of the hardware.
 

charlie

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What can be an alternative device if i need ipv6?

Edit: I found some IPv6 routing related thinks in the documentation, so is that not true?
 
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fohdeesha

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there's a LOT of stuff in that docu that doesn't apply. no ipv6 routing. you can assign ipv6 addresses to management interfaces and stuff (on brocade fw anyway) but no routing
 

TheBloke

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Edit: I found some IPv6 routing related thinks in the documentation, so is that not true?
For LB6M on Brocade FastIron software, this is the doc that describes exactly what the TurboIron 24X - and therefore the LB6M once flashed - can do: TurboIron24x_08001_ConfigGuide.pdf.

Pre-flash, on FastPath, will be a bit different. Earlier in this thread someone has posted various docs, but they're not nearly as complete as the Brocade docs, and again probably don't exactly apply to the LB6M.

In either scenario there's no ipv6 routing as the switch lacks necessary hardware support.

The LB6M is a reference Brocade design that was never sold to the public, but rather sold by Quanta first to Microsoft and then later also into Amazon and maybe some other big companies. The models we all have were made for Amazon. So there's never been a proper published manual for it. But the Brocade TurboIron was sold publicly and was kept updated (at least until last year) and is well documented. It's identical in all respects to the LB6M, besides a couple of non-vital things like port LED lights and the management port. The result being that once the LB6M is flashed to Brocade FastIron, it works as per that doc above, except the LEDs on the 10G ports don't work, you only get one management port, and that management port is a bit odd (it will default to 100mbit half duplex on every hard power cycle, requiring a special command to fix.)
 
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