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Racking Mac Pros

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Re: Racking Mac Pros

#171

Post by skuhn »

chiph wrote: post #130
skuhn wrote: post #107

Earlier quoted context omitted.

They're pretty much silent relative to datacenter stuff. One of the goals of the next revision is to have LED power indicators (maybe plugged in to the front USB ports) or LCD panels built into the front of the chassis. Right now you actually can't tell that the rack is powered on unless you walk to the hot aisle and look at the power readouts, it's that quiet.

Is fan failure reported through management APIs?

We wrote a little tool to probe SMC and graph the output, so we know CPU temp and fan speeds and whatnot. If a fan were to fail, it shows up as 0 rpm speed (in my experience thus far), so we can tell and take the host offline.

Even if you can't see when the fan itself has failed, the CPU core temp should eventually go out of the acceptable range without any forced air at all, which is also helpful to determine that hardware maintenance is required.

So far nothing has actually failed on any of our Mac Pros though. When and if that happens, the entire Pro will get swapped out as one field replaceable unit, and then put in the repair queue.

Re: Racking Mac Pros

#172

Post by skuhn »

chx wrote: post #154

IF that's what you want, that's a fairly ingenious solution. If you look at https://macstadium.com/mac-pro you'd think you can just build the racks with the Mac Pro opening back and front. But it's 6.6" inches wide so you can only have two, three would be more than 19" (and you can't put 19" of equipment inside a rack). But this way you can squeeze four in the same space and since the cylinder is 9.9" high if you'd n…

For our use case, the disk portion doesn't live on the Mac Pros (we have Linux systems that act as storage servers).

We toyed with open shelf type solutions that would let us mount the systems front-to-back, but as you noted, anything above 2 Mac Pros across won't fit in a 19" rack. We also thought about mounting 23" rails in our standard cabinet, but ultimately settled on this chassis and orientation.

One of our early design ideas: https://www.dropbox.com/s/15u19aivay4hfiu/2014-01-13%2017.14...

Re: Racking Mac Pros

#174

Post by skuhn »

15155 wrote: post #102
skuhn wrote: post #28

Earlier quoted context omitted.

(I'm the datacenter manager at imgix and wrote this post) From a pure hardware perspective, I would love to move this part of the service to Linux systems with GPUs. I spent some time evaluating this before we committed to the Mac Pro solution -- built some prototype hardware and did a cost analysis. It just wasn't the right move, because of the engineering cost for us. OS X's graphics pipeline is really strong, and…

> who may be prone to pass on theories of how things work rather than facts This is the biggest nightmare about working with OS X, to me. Any forum discussion you find on Macrumors or the Apple forums is hilariously misguided with pathetically bad "theories" on why something isn't working and how to fix it. "Zap the PRAM!" can be found in any/every thread, and that's a mild example.

Zapping the PRAM is a pretty frequent joke around the office.

There are some OS X groups that are more focused on automated deployments for IT type stuff, so those can often be a source of more enlightened discourse, even though it still isn't exactly catering to our niche.

Re: Racking Mac Pros

#175

Post by Ded7xSEoPKYNsDd »

Someone wrote: post #141
MrBuddyCasino wrote: post #127

Earlier quoted context omitted.

Depends on where you live. At least in Germany (and I think the whole EU), EULAs are meaningless.

I can't find that for EULA's proper (would surprise me, too, as that would allow anyone to pirate any shrink-wrapped software), but EULAs cannot prohibit selling your license: that was upheld for software bought by download, too: http://curia.europa.eu/jcms/upload/docs/application/pdf/2012... : "Where the copyright holder makes available to his customer a copy – tangible or intangible – and at the same time concludes…

Afaik, if the EULA is only shown after the sale has already taken place, it is basically meaningless around here. But IANAL and only relaying what I heard on the internet.

Re: Racking Mac Pros

#176

Post by pdeuchler »

TD-Linux wrote: post #168
smackfu wrote: post #147

Earlier quoted context omitted.

I assume 99% of users are using downsampling, to get thumbnails.

CHROME ON MAC USERS: Use the imgur links instead of the 0x0 links, some users seem to be reporting crashes related to TLS. The downsampling also isn't that great. Original image: https://raw.githubusercontent.com/haasn/cms/master/rings_lg_... Downsampled with imgix: http://chen.imgix.net/rings_lg_orig.png?w=400 Downsampled with imagemagick: https://0x0.st/1-.png http://i.imgur.com/Nvl7tAm.png Downsampled with imagema…

Just FYI both of those 0x0.st images crash Chrome (Version 42.0.2311.135 (64-bit)) for me and several colleagues...

You don't even have to click the link, just simply get Chrome to load it into memory

edit: looks like something to do with Chrome's pre-fetching and https cert parsing, I think they're literally parsing the "0x0" string within the cert as a memory location

Re: Racking Mac Pros

#177

Post by Geee »

TD-Linux wrote: post #168
smackfu wrote: post #147

Earlier quoted context omitted.

I assume 99% of users are using downsampling, to get thumbnails.

CHROME ON MAC USERS: Use the imgur links instead of the 0x0 links, some users seem to be reporting crashes related to TLS. The downsampling also isn't that great. Original image: https://raw.githubusercontent.com/haasn/cms/master/rings_lg_... Downsampled with imgix: http://chen.imgix.net/rings_lg_orig.png?w=400 Downsampled with imagemagick: https://0x0.st/1-.png http://i.imgur.com/Nvl7tAm.png Downsampled with imagema…

Opening the 0x0.st image crashes Chrome on Mac. Just Googling 0x0.st causes whole browser to crash!

Re: Racking Mac Pros

#178

Post by skuhn »

sp332 wrote: post #101
skuhn wrote: post #65

Earlier quoted context omitted.

(I'm the datacenter manager at imgix, and wrote this post) Yep, there are lots of other options out there. I considered at least 4 or 5 off-the-shelf ones before committing to designing and building our own. In Sonnet's case, it is super expensive and no denser than this: http://mk1manufacturing.com/store/cart.php?m=product_detail&... We're able to achieve twice that density, which put it right on target with where I…

Yeah I saw it was half the density. Too bad they're so expensive. On the plus side... you can actually buy them :)

True, but now you can buy our chassis from our rack integrator (in sufficient quantities), and I'm hoping they'll be able to open source the design. If you're in the market, contact me.

Re: Racking Mac Pros

#179

Post by skuhn »

anoother wrote: post #162

It would be interesting, once these have been in use for a while, to see some stats on the relative temperatures (+ fan speeds) of each machine within the enclosure. I can imagine the dynamics of 4 machines scavenging air from a single chamber, with an opening on one end, will result in the machines nearer the warm aisle having to work harder to keep cool... I also wonder what kind of ducting could be implemented to…

I'm graphing this type of data, but it's too early to draw firm conclusions. I was mainly concerned that the upper, rear units might not fit within my desired thermal envelope, but so far it hasn't been an issue at all. This might make it into our follow-up post, which is intended to explore the design decisions behind the chassis.

If heat or airflow did become a problem, we could add fans to the chassis (either in the intake tunnel or along the exhaust vent). The ideal solution is probably to also attach a chimney to the rear of the rack, but so far it hasn't been necessary.

Re: Racking Mac Pros

#180

Post by scott_s »

skuhn wrote: post #87
hashtree wrote: post #62

Earlier quoted context omitted.

This should be at the top of the article to hush folks like myself who might be curious from the get go why another approach wasn't taken and why the Mac Pros were selected. Thanks for the insight as to the why.

It was something that I struggled with while writing the article -- you don't want to introduce your solution as "well, this sucks in various ways, but keep reading...". It does boil down to viewing things pragmatically though. The Macs present challenges, but by our math, they're worth it relative to the cost of doing something else and the benefits they provide. And we actually run a lot of them in production, so I…

You do want to introduce your solution with "this has problems A, B and C, but we went with it because of X, Y and Z." It becomes much more interesting, because you're explaining not just your solution, but the problem space. Just the solution is usually less interesting than why the solution, even with its downsides, solves your problem.

By the way, thanks for clearly, completely and patiently responding to people in this thread.

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