Know How... 280

We go to the KnowHow community and answer your questions! Time to upgrade you NAS? What is the Raspberry Pi compute module and why would you want it. What's the best way to exhaust hot air, and more!

Synology NAS Question        
-- Alex Martinez        
"Im thinking of getting a synology ds1515+ but im debating if i should wait a bit that maybe its about time synology will release a newer model? Should i just buy or wait a bit?"        
        
1515+ Specs:        
* 5 Hot-swap bays (maximum of 10TB each)        
* Supports SSD Caching on Bay 1 (Install an SSD into bay 1 and the rest of the array is cached onto it)        
* Quad-core 2.4Ghz Intel Atom CPU        
* 2GB of DDR3 (Expandable to 6GB) (One empty slot)        
* Dedicated HARDWARE encryption engine        
* 4 GigE ports with failover and link aggregation (bonding)        
* Scalable with up to 2 expansion units (through the eSATA port)        
* 4x USB 3.0 ports on the back        
* 2 eSATA Ports        
        
* 450.77MB/s read /// 395MB/s Write        
(NB: That's 3.6GBps read // 3.16Gbps write :: That means it's FASTER than a single GigE interface can handle. You'll be WASTING that speed unless you got a switch/computer than can bind multiple GigE pipes OR if you're in a workgroup w/multiple computers accessing the NAS as the same time)        
        
* Dedicated HARDWARE encryption engine (Drops throughput to 448/191)        
* Supports wireless dongle support (to act as AP)        
        
        
Fan Direction        
-- Dennis Millican        
"I am building a LED array of 3W LEDs mounted on a .25 inch aluminum plate for a grow light.  To cool it, I plan to mount a couple of fans on the back side. My question is should I mount the fans to blow cool air toward the aluminum or to exhaust warm air away from the LEDs?  I am leaning toward blowing cool air toward the aluminum plate."        
        
* This is an issue that system builders have been playing with for decades        
* Should I blow air INTO the case, or suck it out?        
* We've more or less agreed that it's always good to have BOTH positive and negative pressure        
        
NB:        
* In an "OPEN" system, it's better to blow air over the heat diffusion surface        
* In a "CLOSED" system, you could get away with using it as an exhaust fan ASSUMING that the incoming air will flow over the heat diffusion surface        

<p><b>Connect with us!</b></p><ul><li>Don't forget to check out our large library of projects at <a href="https://twit.tv/shows/know-how">https://twit.tv/shows/know-how</a>.</li… our <a href="https://plus.google.com/communities/102778909882340711425&quot; target="_blank">Google+ Community</a>.</li><li>Tweet at us at <a href="https://twitter.com/PadreSJ&quot; target="_blank">@PadreSJ</a>, <a href="https://twitter.com/Cranky_Hippo&quot; target="_blank">@Cranky_Hippo</a>, and <a href="https://twitter.com/Anelf3&quot; target="_blank">@Anelf3</a>.</li></ul><p>Thanks to <a href="https://www.cachefly.com/&quot; target="_blank">CacheFly</a> for the bandwidth for this show.</p>