Re: [eX-bulk] : Re: Rasberry pi - high density
Greetings, Do we really need them to be swappable at that point? The reason we swap HDD's (if we do) is because they are rotational, and mechanical things break. Do we swap CPUs and memory hot? Do we even replace memory on a server that's gone bad, or just pull the whole thing during the periodic dead body collection and replace it? Might it not be more efficient (and space saving) to just add 20% more storage to a server than the design goal, and let the software use the extra space to keep running when an SSD fails? When the overall storage falls below tolerance, the unit is dead. I think we will soon need to (if we aren't already) stop thinking about individual components as FRUs. The server (or rack, or container) is the FRU. Christopher On 9 May 2015, at 12:26, Eugeniu Patrascu wrote: On Sat, May 9, 2015 at 9:55 PM, Barry Shein b...@world.std.com wrote: On May 9, 2015 at 00:24 char...@thefnf.org (char...@thefnf.org) wrote: So I just crunched the numbers. How many pies could I cram in a rack? For another list I just estimated how many M.2 SSD modules one could cram into a 3.5 disk case. Around 40 w/ some room to spare (assuming heat and connection routing aren't problems), at 500GB/each that's 20TB in a standard 3.5 case. It's getting weird out there. I think the next logical step in servers would be to remove the traditional hard drive cages and put SSD module slots that can be hot swapped. Imagine inserting small SSD modules on the front side of the servers and directly connect them via PCIe to the motherboard. No more bottlenecks and a software RAID of some sorts would actually make a lot more sense than the current controller based solutions. -- 李柯睿 Avt tace, avt loqvere meliora silentio Check my PGP key here: http://www.asgaard.org/cdl/cdl.asc Current vCard here: http://www.asgaard.org/cdl/cdl.vcf keybase: https://keybase.io/liljenstolpe
Re: [eX-bulk] : Re: Rasberry pi - high density
On 2015-05-13 19:42, na...@cdl.asgaard.org wrote: Greetings, Do we really need them to be swappable at that point? The reason we swap HDD's (if we do) is because they are rotational, and mechanical things break. Right. Do we swap CPUs and memory hot? Nope. Usually just toss the whole thing. Well I keep spare ram around cause it's so cheap. But if CPU goes, chuck it in the ewaste pile in the back. Do we even replace memory on a server that's gone bad, or just pull the whole thing during the periodic dead body collection and replace it? Usually swap memory. But yeah, often times the hardware ops folks just cull old boxes on a quarterly basis and backfill with the latest batch of inbound kit. At large scale (which many on this list operate at), you have pallets of gear sitting in the to deploy queue, and another couple pallets worth racked up but not even imaged yet. (This is all supposition of course. I'm used to working with $HUNDREDS of racks worth of gear). Containers, moonshot type things etc are certainly on the radar. Might it not be more efficient (and space saving) to just add 20% more storage to a server than the design goal, and let the software use the extra space to keep running when an SSD fails? Yes. Also a few months ago I read an article about several SSD brands having $MANY terabytes written to them. Can't find it just now. But they seem to take quite a long time (data wise/number of write wise) to fail. When the overall storage falls below tolerance, the unit is dead. I think we will soon need to (if we aren't already) stop thinking about individual components as FRUs. The server (or rack, or container) is the FRU. Christopher Yes. Agree. Most of the very large scale shops (the ones I've worked at) are massively horizontal scaled, cookie cutter. Many boxes replicating/extending/expanding a set of well defined workloads.
Re: Rasberry pi - high density
On 05/11/2015 06:50 PM, Brandon Martin wrote: 8kW/rack is something it seems many a typical computing oriented datacenter would be used to dealing with, no? Formfactor within the rack is just a little different which may complicate how you can deliver the cooling - might need unusually forceful forced air or a water/oil type heat exchanger for the oil immersion method being discussed elsewhere in the thread. You still need giant wires and busses to move 800A worth of current. ... This thread brings me back to 1985, what with talk of full immersion cooling (Fluorinert, anyone?) and hundreds of amps at 5VDC reminds me of the Cray-2, which dropped 150-200KW in 6 rack location units of space; 2 for the CPU itself, 2 for space, and 2 for the cooling waterfall [ https://en.wikipedia.org/wiki/File:Cray2.jpeg by referencing floor tile space occupied and taking 16 sq ft (four tiles) as one RLU ]. Each 'stack' of the CPU pulled 2,200A at 5V [source: https://en.wikipedia.org/wiki/Cray-2#History ]. At those currents you use busbar, not wire. Our low-voltage (120/208V three-phase) switchgear here uses 6,000A rated busbar, so it's readily available, if expensive.
Re: Rasberry pi - high density
To some extent people are comparing apples (not TM) and oranges. Are you trying to maximize the number of total cores or the number of total computes? They're not the same. It depends on the job mix you expect. For example a map-reduce kind of problem, search of a massive database, probably is improved with lots of cores even if each core isn't that fast. You partition a database across thousands of cores and broadcast who has XYZ? and wait for an answer, in short. There are a lot of problems like that, and a lot of problems which cannot be improved by lots of cores. For example if you have to wait for one answer before you can compute the next (matrix inversion is notorious for this property and very important.) You just can't keep the pipeline filled. And then there are the relatively inexpensive GPUs which can do many floating point ops in parallel and are good at certain jobs like, um, graphics! rendering, ray-tracing, etc. But they're not very good at general purpose integer ops like string searching, as a general rule, or problems which can't be decomposed to take advantage of the parallelism. You've got your work cut out for you analyzing these things! -- -Barry Shein The World | b...@theworld.com | http://www.TheWorld.com Purveyors to the Trade | Voice: 800-THE-WRLD| Dial-Up: US, PR, Canada Software Tool Die| Public Access Internet | SINCE 1989 *oo*
Re: Rasberry pi - high density
Here's someone's comparison between the B and B+ in terms of power: http://raspi.tv/2014/how-much-less-power-does-the-raspberry-pi-b-use-than-the-old-model-b On Mon, May 11, 2015 at 10:25 PM, Joel Maslak jmas...@antelope.net wrote: Rather then guessing on power consumption, I measured it. I took a Pi (Model B - but I suspect B+ and the new version is relatively similar in power draw with the same peripherials), hooked it up to a lab power supply, and took a current measurement. My pi has a Sandisk SD card and a Sandisk USB stick plugged into it, so, if anything, it will be a bit high in power draw. I then fired off a tight code loop and a ping -f from another host towards it, to busy up the processor and the network/USB on the Pi. I don't have a way of making the video do anything, so if you were using that, your draw would be up. I also measured idle usage (sitting at a command prompt). Power draw was 2.3W under load, 2.0W at idle. If it was my project, I'd build a backplane board with USB-to-ethernet and ethernet switch chips, along with sockets for Pi compute modules (or something similar). I'd want one power cable and one network cable per backplane board if my requirements allowed it. Stick it all in a nice card cage and you're done. As for performance per watt, I'd be surprised if this beat a modern video processor for the right workload. On Mon, May 11, 2015 at 5:16 PM, Rafael Possamai raf...@gav.ufsc.br wrote: Maybe I messed up the math in my head, my line of thought was one pi is estimated to use 1.2 watts, whereas the nuc is at around 65 watts. 10 pi's = 12 watts. My comparison was 65watts/12watts = 5.4 times more power than 10 pi's put together. This is really a rough estimate because I got the NUC's power consumption from the AC/DC converter that comes with it, which has a maximum output of 65 watts. I could be wrong (up to 5 times) and still the pi would use less power. Now that I think about it, the best way to simplify this is to calculate benchmark points per watt, so rasp pi is at around 406/1.2 which equals 338. The NUC, roughly estimated to be at 3857/65 which equals 60. Let's be very skeptical and say that at maximum consumption the pi is using 5 watts, then 406/5 is around 81. At this point the rasp pi still scores better. Only problem we are comparing ARM to x86 which isn't necessarily fair (i am not an expert in computer architectures) On Mon, May 11, 2015 at 5:24 PM, Hugo Slabbert h...@slabnet.com wrote: Did I miss anything? Just a quick comparison. If those numbers are accurate, then it leans towards the NUC rather than the Pi, no? Perf: 1x i5 NUC = 10x Pi $$: 1x i5 NUC = 10x Pi Power: 1x i5 NUC = 5x Pi So...if a single NUC gives you the performance of 10x Pis at the capital cost of 10x Pis but uses half the power of 10x Pis and only a single Ethernet port, how does the Pi win? -- Hugo On Mon 2015-May-11 17:08:43 -0500, Rafael Possamai raf...@gav.ufsc.br wrote: Interesting! Knowing a pi costs approximately $35, then you need approximately $350 to get near an i5.. The smallest and cheapest desktop you can get that would have similar power is the Intel NUC with an i5 that goes for approximately $350. Power consumption of a NUC is about 5x that of the raspberry pi, but the number of ethernet ports required is 10x less. Usually in a datacenter you care much more about power than switch ports, so in this case if the overhead of controlling 10x the number of nodes is worth it, I'd still consider the raspberry pi. Did I miss anything? Just a quick comparison. On Mon, May 11, 2015 at 4:40 PM, Michael Thomas m...@mtcc.com wrote: As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve
Re: Rasberry pi - high density
Interesting! Knowing a pi costs approximately $35, then you need approximately $350 to get near an i5.. The smallest and cheapest desktop you can get that would have similar power is the Intel NUC with an i5 that goes for approximately $350. Power consumption of a NUC is about 5x that of the raspberry pi, but the number of ethernet ports required is 10x less. Usually in a datacenter you care much more about power than switch ports, so in this case if the overhead of controlling 10x the number of nodes is worth it, I'd still consider the raspberry pi. Did I miss anything? Just a quick comparison. On Mon, May 11, 2015 at 4:40 PM, Michael Thomas m...@mtcc.com wrote: As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. -c
Re: Rasberry pi - high density
As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. -c
Re: Rasberry pi - high density
On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. -c
Re: Rasberry pi - high density
On Mon, May 11, 2015 at 1:37 PM, Clay Fiske c...@bloomcounty.org wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi The parallella board is about the same size and has interesting properties all by itself. In addition to ethernet it also brings out a lot of pins. http://www.adapteva.com/parallella-board/ there are also various and sundry quad core arm boards in the same form factor. Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. Dip them all in a vat of oil. -- Dave Täht Open Networking needs **Open Hardware** https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67
Re: Rasberry pi - high density
Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi You butt up against major power/heat issues here in a single rack, not that it's impossible. From what I could find the rPi2 requires .5A min. The few SSD specs that I could find required something like .8 - 1.6A. Assuming that part of .5A is for driving a SSD, 1A/pi would be an optimistic requirement. So 825-1600 amp in a single rack. It's not crazy to throw 120AMP in a rack for higher density but you would need room to put a PDU ever 2 u or so if you were running a 30amp circus. That's before switching infrastructure. You'll also need airflow since that's not built into the pi. I've seen guys do this with mac minis and they end up needing to push everything back in the rack 4 inches to put 3 or 4 fans with 19in blades on the front door to make the airflow data center ready. So to start, you'd probably need to take a row out of the front of the rack for fans and a row out of the back for power. Cooling isn't really an issue since you can cool anything that you can blow air on[1]. At 825 rpi @ 1Amp each, you'd get about 3000 btu/h (double for the higher power estimate). You'd need need 3-6 tons of avalible cooling capacity without redundancy. I don't know how to do the math for the 'vat of oil scenario'. It's not something I've ever wanted to work with. In the end, I think you end up putting way too much money (power/cooling) into the redundant green board around the CPU. This feels like it should be a Friday thread. :) Maybe I'm having a read only may 10-17. 1. Please don't list the things that can't be cooled by blowing air. -- Pete
Re: Rasberry pi - high density
Rather then guessing on power consumption, I measured it. I took a Pi (Model B - but I suspect B+ and the new version is relatively similar in power draw with the same peripherials), hooked it up to a lab power supply, and took a current measurement. My pi has a Sandisk SD card and a Sandisk USB stick plugged into it, so, if anything, it will be a bit high in power draw. I then fired off a tight code loop and a ping -f from another host towards it, to busy up the processor and the network/USB on the Pi. I don't have a way of making the video do anything, so if you were using that, your draw would be up. I also measured idle usage (sitting at a command prompt). Power draw was 2.3W under load, 2.0W at idle. If it was my project, I'd build a backplane board with USB-to-ethernet and ethernet switch chips, along with sockets for Pi compute modules (or something similar). I'd want one power cable and one network cable per backplane board if my requirements allowed it. Stick it all in a nice card cage and you're done. As for performance per watt, I'd be surprised if this beat a modern video processor for the right workload. On Mon, May 11, 2015 at 5:16 PM, Rafael Possamai raf...@gav.ufsc.br wrote: Maybe I messed up the math in my head, my line of thought was one pi is estimated to use 1.2 watts, whereas the nuc is at around 65 watts. 10 pi's = 12 watts. My comparison was 65watts/12watts = 5.4 times more power than 10 pi's put together. This is really a rough estimate because I got the NUC's power consumption from the AC/DC converter that comes with it, which has a maximum output of 65 watts. I could be wrong (up to 5 times) and still the pi would use less power. Now that I think about it, the best way to simplify this is to calculate benchmark points per watt, so rasp pi is at around 406/1.2 which equals 338. The NUC, roughly estimated to be at 3857/65 which equals 60. Let's be very skeptical and say that at maximum consumption the pi is using 5 watts, then 406/5 is around 81. At this point the rasp pi still scores better. Only problem we are comparing ARM to x86 which isn't necessarily fair (i am not an expert in computer architectures) On Mon, May 11, 2015 at 5:24 PM, Hugo Slabbert h...@slabnet.com wrote: Did I miss anything? Just a quick comparison. If those numbers are accurate, then it leans towards the NUC rather than the Pi, no? Perf: 1x i5 NUC = 10x Pi $$: 1x i5 NUC = 10x Pi Power: 1x i5 NUC = 5x Pi So...if a single NUC gives you the performance of 10x Pis at the capital cost of 10x Pis but uses half the power of 10x Pis and only a single Ethernet port, how does the Pi win? -- Hugo On Mon 2015-May-11 17:08:43 -0500, Rafael Possamai raf...@gav.ufsc.br wrote: Interesting! Knowing a pi costs approximately $35, then you need approximately $350 to get near an i5.. The smallest and cheapest desktop you can get that would have similar power is the Intel NUC with an i5 that goes for approximately $350. Power consumption of a NUC is about 5x that of the raspberry pi, but the number of ethernet ports required is 10x less. Usually in a datacenter you care much more about power than switch ports, so in this case if the overhead of controlling 10x the number of nodes is worth it, I'd still consider the raspberry pi. Did I miss anything? Just a quick comparison. On Mon, May 11, 2015 at 4:40 PM, Michael Thomas m...@mtcc.com wrote: As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling.
Re: Rasberry pi - high density
- On May 11, 2015, at 5:36 PM, Peter Baldridge petebaldri...@gmail.com wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi You butt up against major power/heat issues here in a single rack, not that it's impossible. From what I could find the rPi2 requires .5A min. The few SSD specs that I could find required something like .8 - 1.6A. Assuming that part of .5A is for driving a SSD, 1A/pi would be an optimistic requirement. So 825-1600 amp in a single rack. It's not crazy to throw 120AMP in a rack for higher density but you would need room to put a PDU ever 2 u or so if you were running a 30amp circus. That is .8-1.6A at 5v DC. A far cry from 120V AC. We're talking ~5W versus ~120W each. Granted there is some conversion overhead, but worst case you are probably talking about 1/20th the power you describe. -Randy
Re: Rasberry pi - high density
On Mon, May 11, 2015 at 3:21 PM, Randy Carpenter rcar...@network1.net wrote: That is .8-1.6A at 5v DC. A far cry from 120V AC. We're talking ~5W versus ~120W each. Granted there is some conversion overhead, but worst case you are probably talking about 1/20th the power you describe. Yeah, missed that. You'd still need fans probably for air flow but the power would be a non issue. -- Pete
Re: Rasberry pi - high density
On Mon, 2015-05-11 at 14:36 -0700, Peter Baldridge wrote: I don't know how to do the math for the 'vat of oil scenario'. It's not something I've ever wanted to work with. It's pretty interesting what you can do with immersion cooling. I work with it at $DAYJOB. Similar to air cooling, but your coolant flow rates are much lower than air, and you don't need any fans in the systems--The pumps take the place of those. We save a lot of money on the cooling side, since we don't need to compress and expand gases/liquids. We can run with warmish (25-30C) water from cooling towers, and still keep the systems at a target temperature of 35C. --Chris
Re: Rasberry pi - high density
On 05/11/2015 06:21 PM, Randy Carpenter wrote: That is .8-1.6A at 5v DC. A far cry from 120V AC. We're talking ~5W versus ~120W each. Granted there is some conversion overhead, but worst case you are probably talking about 1/20th the power you describe. His estimates seem to consider that it's only 5V, though. He has 825 Pis per rack at ~5-10W each is call it ~8kW on the high end. 8kW is 2.25 tons of refrigeration at first cut, plus any power conversion losses, losses in ducting/chilled water distribution, etc. Calling for at least 3 tons of raw cooling capacity for this rack seems reasonable. 8kW/rack is something it seems many a typical computing oriented datacenter would be used to dealing with, no? Formfactor within the rack is just a little different which may complicate how you can deliver the cooling - might need unusually forceful forced air or a water/oil type heat exchanger for the oil immersion method being discussed elsewhere in the thread. You still need giant wires and busses to move 800A worth of current. It almost seems like you'd have to rig up some sort of 5VDC bus bar system along the sides of the cabinet and tap into it for each shelf or (probably the approach I'd look at first, instead) give up some space on each shelf or so for point-of-load power conversion (120 or 240VAC to 5VDC using industrial brick style supplies or similar) and conventional AC or high voltage (in this context, 48 or 380V is high) DC distribution to each shelf. Getting 800A at 5V to the rack with reasonable losses is going to need humongous wires, too. Looks like NEC calls for something on the order of 800kcmil under rosy circumstances just to move it safely (which, at only 5V, is not necessarily effectively) - yikes that's a big wire. -- Brandon Martin
Re: Rasberry pi - high density
Maybe I messed up the math in my head, my line of thought was one pi is estimated to use 1.2 watts, whereas the nuc is at around 65 watts. 10 pi's = 12 watts. My comparison was 65watts/12watts = 5.4 times more power than 10 pi's put together. This is really a rough estimate because I got the NUC's power consumption from the AC/DC converter that comes with it, which has a maximum output of 65 watts. I could be wrong (up to 5 times) and still the pi would use less power. Now that I think about it, the best way to simplify this is to calculate benchmark points per watt, so rasp pi is at around 406/1.2 which equals 338. The NUC, roughly estimated to be at 3857/65 which equals 60. Let's be very skeptical and say that at maximum consumption the pi is using 5 watts, then 406/5 is around 81. At this point the rasp pi still scores better. Only problem we are comparing ARM to x86 which isn't necessarily fair (i am not an expert in computer architectures) On Mon, May 11, 2015 at 5:24 PM, Hugo Slabbert h...@slabnet.com wrote: Did I miss anything? Just a quick comparison. If those numbers are accurate, then it leans towards the NUC rather than the Pi, no? Perf: 1x i5 NUC = 10x Pi $$: 1x i5 NUC = 10x Pi Power: 1x i5 NUC = 5x Pi So...if a single NUC gives you the performance of 10x Pis at the capital cost of 10x Pis but uses half the power of 10x Pis and only a single Ethernet port, how does the Pi win? -- Hugo On Mon 2015-May-11 17:08:43 -0500, Rafael Possamai raf...@gav.ufsc.br wrote: Interesting! Knowing a pi costs approximately $35, then you need approximately $350 to get near an i5.. The smallest and cheapest desktop you can get that would have similar power is the Intel NUC with an i5 that goes for approximately $350. Power consumption of a NUC is about 5x that of the raspberry pi, but the number of ethernet ports required is 10x less. Usually in a datacenter you care much more about power than switch ports, so in this case if the overhead of controlling 10x the number of nodes is worth it, I'd still consider the raspberry pi. Did I miss anything? Just a quick comparison. On Mon, May 11, 2015 at 4:40 PM, Michael Thomas m...@mtcc.com wrote: As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. -c
Re: Rasberry pi - high density
Did I miss anything? Just a quick comparison. If those numbers are accurate, then it leans towards the NUC rather than the Pi, no? Perf: 1x i5 NUC = 10x Pi $$: 1x i5 NUC = 10x Pi Power: 1x i5 NUC = 5x Pi So...if a single NUC gives you the performance of 10x Pis at the capital cost of 10x Pis but uses half the power of 10x Pis and only a single Ethernet port, how does the Pi win? -- Hugo On Mon 2015-May-11 17:08:43 -0500, Rafael Possamai raf...@gav.ufsc.br wrote: Interesting! Knowing a pi costs approximately $35, then you need approximately $350 to get near an i5.. The smallest and cheapest desktop you can get that would have similar power is the Intel NUC with an i5 that goes for approximately $350. Power consumption of a NUC is about 5x that of the raspberry pi, but the number of ethernet ports required is 10x less. Usually in a datacenter you care much more about power than switch ports, so in this case if the overhead of controlling 10x the number of nodes is worth it, I'd still consider the raspberry pi. Did I miss anything? Just a quick comparison. On Mon, May 11, 2015 at 4:40 PM, Michael Thomas m...@mtcc.com wrote: As it turns out, I've been playing around benchmarking things lately using the tried and true UnixBench suite and here are a few numbers that might put this in some perspective: 1) My new Rapsberry pi (4 cores, arm): 406 2) My home i5-like thing (asus 4 cores, 16gb's from last year): 3857 3) AWS c4.xlarge (4 cores, ~8gb's): 3666 So you'd need to, uh, wedge about 10 pi's to get one half way modern x86. Mike On 5/11/15 1:37 PM, Clay Fiske wrote: On May 8, 2015, at 10:24 PM, char...@thefnf.org wrote: Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol… This feels like it should be a Friday thread. :) If you’re really going for density: - At 0.83 inches high you could go 2x per U (depends on your mounting system and how much space it burns) - I’d expect you could get at least 7 wide if not 8 with the right micro-USB power connector - In most datacenter racks I’ve seen you could get at least 8 deep even with cable breathing room So somewhere between 7x8x2 = 112 and 8x8x2 = 128 per U. And if you get truly creative about how you stack them you could probably beat that without too much effort. This doesn’t solve for cooling, but I think even at these numbers you could probably make it work with nice, tight cabling. -c signature.asc Description: Digital signature
Re: Rasberry pi - high density
On Sat, May 9, 2015 at 11:55 AM, Barry Shein b...@world.std.com wrote: On May 9, 2015 at 00:24 char...@thefnf.org (char...@thefnf.org) wrote: So I just crunched the numbers. How many pies could I cram in a rack? For another list I just estimated how many M.2 SSD modules one could cram into a 3.5 disk case. Around 40 w/ some room to spare (assuming heat and connection routing aren't problems), at 500GB/each that's 20TB in a standard 3.5 case. I could see liquid cooling such a device. insert the whole thing into oil. how many pcie slots are allowed in the standards? It's getting weird out there. Try to project your mind forward another decade with capability/cost like this: http://www.digitaltrends.com/computing/nine-dollar-computer-kickstarter/ I hope humanity´s last act will be to educate the spambots past their current puerile contemplation of adolescent fantasies and into contemplating faust. -- -Barry Shein The World | b...@theworld.com | http://www.TheWorld.com Purveyors to the Trade | Voice: 800-THE-WRLD| Dial-Up: US, PR, Canada Software Tool Die| Public Access Internet | SINCE 1989 *oo* -- Dave Täht Open Networking needs **Open Source Hardware** https://plus.google.com/u/0/+EricRaymond/posts/JqxCe2pFr67
Re: Rasberry pi - high density
From the work that I've done in the past with clusters, your need for bandwidth is usually not the biggest issue. When you work with big data, let's say 500 million data points, most mathematicians would condense it all down into averages, standard deviations, probabilities, etc, which then become much smaller to save in your hard disks and also to perform data analysis with, as well as transfer these stats from master to nodes and vice-versa. So for one project at a time, your biggest concern is cpu clock, ram, interrupts, etc. If you want to run all of the BIG 10s academic projects into one big cluster for example, then networking might become an issue solely due to volume. The more data you transfer, the longer it would take to perform any meaningful analysis on it, so really your bottleneck is TFLOPS rather than packets per second. With Facebook it's the opposite, it's mostly pictures and videos of cats coming in and out of the server with lots of reads and writes on their storage. In that case, switching tbps of traffic is how they make money. A good example is creating a dockr container with your application and deploying a cluster with CoreOS. You save all that capex and spend by the hour. I believe Azure and EC2 already have support for CoreOS. On Sat, May 9, 2015 at 12:48 AM, Tim Raphael raphael.timo...@gmail.com wrote: The problem is, I can get more processing power and RAM out of two 10RU blade chassis and only needing 64 10G ports... 32 x 256GB RAM per blade = 8.1TB 32 x 16 cores x 2.4GHz = 1,228GHz (not based on current highest possible, just using reasonable specs) Needing only 4 QFX5100s which will cost less than a populated 6513 and give lower latency. Power, cooling and cost would be lower too. RPi = 900MHz and 1GB RAM. So to equal the two chassis, you'll need: 1228 / 0.9 = 1364 Pis for compute (main performance aspect of a super computer) meaning double the physical space required compared to the chassis option. So yes, infeasible indeed. Regards, Tim Raphael On 9 May 2015, at 1:24 pm, char...@thefnf.org wrote: So I just crunched the numbers. How many pies could I cram in a rack? Check my numbers? 48U rack budget 6513 15U (48-15) = 33U remaining for pie 6513 max of 576 copper ports Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol...
Re: Rasberry pi - high density
On May 9, 2015 at 00:24 char...@thefnf.org (char...@thefnf.org) wrote: So I just crunched the numbers. How many pies could I cram in a rack? For another list I just estimated how many M.2 SSD modules one could cram into a 3.5 disk case. Around 40 w/ some room to spare (assuming heat and connection routing aren't problems), at 500GB/each that's 20TB in a standard 3.5 case. It's getting weird out there. -- -Barry Shein The World | b...@theworld.com | http://www.TheWorld.com Purveyors to the Trade | Voice: 800-THE-WRLD| Dial-Up: US, PR, Canada Software Tool Die| Public Access Internet | SINCE 1989 *oo*
Re: Rasberry pi - high density
On Sat, May 9, 2015 at 9:55 PM, Barry Shein b...@world.std.com wrote: On May 9, 2015 at 00:24 char...@thefnf.org (char...@thefnf.org) wrote: So I just crunched the numbers. How many pies could I cram in a rack? For another list I just estimated how many M.2 SSD modules one could cram into a 3.5 disk case. Around 40 w/ some room to spare (assuming heat and connection routing aren't problems), at 500GB/each that's 20TB in a standard 3.5 case. It's getting weird out there. I think the next logical step in servers would be to remove the traditional hard drive cages and put SSD module slots that can be hot swapped. Imagine inserting small SSD modules on the front side of the servers and directly connect them via PCIe to the motherboard. No more bottlenecks and a software RAID of some sorts would actually make a lot more sense than the current controller based solutions.
Rasberry pi - high density
So I just crunched the numbers. How many pies could I cram in a rack? Check my numbers? 48U rack budget 6513 15U (48-15) = 33U remaining for pie 6513 max of 576 copper ports Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol...
Re: Rasberry pi - high density
The problem is, I can get more processing power and RAM out of two 10RU blade chassis and only needing 64 10G ports... 32 x 256GB RAM per blade = 8.1TB 32 x 16 cores x 2.4GHz = 1,228GHz (not based on current highest possible, just using reasonable specs) Needing only 4 QFX5100s which will cost less than a populated 6513 and give lower latency. Power, cooling and cost would be lower too. RPi = 900MHz and 1GB RAM. So to equal the two chassis, you'll need: 1228 / 0.9 = 1364 Pis for compute (main performance aspect of a super computer) meaning double the physical space required compared to the chassis option. So yes, infeasible indeed. Regards, Tim Raphael On 9 May 2015, at 1:24 pm, char...@thefnf.org wrote: So I just crunched the numbers. How many pies could I cram in a rack? Check my numbers? 48U rack budget 6513 15U (48-15) = 33U remaining for pie 6513 max of 576 copper ports Pi dimensions: 3.37 l (5 front to back) 2.21 w (6 wide) 0.83 h 25 per U (rounding down for Ethernet cable space etc) = 825 pi Cable management and heat would probably kill this before it ever reached completion, but lol...
