A LOOK INSIDE THE SERIAL CABLES SA-ENC12G-01A – CONTINUED
Opening up the SA-ENC12G-01A is incredibly easy. There is a single screw on the back and another on the side. With those removed, the entire side cover slides off exposing the internals. If you squint hard enough, it actually looks like a mini-PC.
On the inside, you can easily see the power supply and main fan. On the left side are the drive bays. The external SAS connectors are mounted to two paddle boards that have cabling coming out of them. These intermediate cables are hard wired to the paddle boards with a large amount of epoxy keeping them in place. We have no worries about these connectors staying secure, but the mounting of the paddle boards gives us a little more concern. The 4-pin power connectors, which are not being used, are pushing against the metal mounting plate, straining the board quite a bit.
Next we have the actual drive backplanes. The SA-ENC12G-01A actually has two of them. They are custom built by Quarch Technology for Serial Cables. Each have two SFF-8643 connectors and two 4-pin power connectors. These backplanes are passive and have no switches, such as a SAS expander.
Finally, we have two small PCBs that are used for the front panel LEDs and the fan power distribution, with the latter housing the piezo buzzer for the alarm.
In the introduction, we mentioned that the form-factor makes it an attractive solution for desktop applications. Once you turn it on for the first time, you will be immediately reminded that it is meant for a server room. To say it is loud is probably an understatement. Saying it is incredibly loud is more accurate. But, in the enterprise world, things aren’t loud for the sake of being loud. They are loud for a reason and the SA-ENC12G-01A is no different. The main fan, located on the back, near the top of the unit, is responsible for the front-to-back airflow and it does a wonderful job at keeping the drives cool. There is also a smaller fan located on the power supply, but it was much quieter than the main fan. In our less than scientific paper test, where we place a piece of paper on the intake (drive carriers) to see if the fans pull enough air to keep the paper from falling, it easily passed. Unfortunately, there is no control over the fan speed. The only setting is full blast.
Using a sound pressure level meter (SPL) with C weighting and slow response, we recorded the following values from 2 feet away.
It is important to note that the reading directly behind the fan is not necessarily noise because the value is affected by the airflow of the fan, but there isn’t an easy way to account for the airflow without affecting the reading. Realistically, we observed a 10-15 dB increase over the ambient noise in our lab, depending on where we measured. Considering the main fan is rated at 52.5dB, our results are not unexpected.
So, what do we get with all of that noise? Cool drives. Not cool in the “fastest SSD on the planet” sense, which they are, but the “never reaching 40C under full load” cool. The maximum temperature we observed was 39C. Considering the 25C ambient temperature of the room and the almost 11W that each HGST drive consumes, these are great results.
It is safe to say that the SA-ENC12G-01A will keep whichever drive you select cool, but we do wish that there was some type of fan control, whether that be temperature controlled or manual.
When it comes enterprise products, power draw is one of the key considerations. Depending on the product, power usage can account for more cost than the actual product over its lifetime. With the SA-ENC12G-01A, there is a single 150W power supply that is responsible for the +5V and +12V rail. This gives you latitude to use SSDs that are becoming increasingly dependent on the +12V rail. For an 8 bay enclosure, 150W should be more than enough to provide power, but the HGST SSD800MM is no common SSD. At 11W, the HGST drive is one of the highest consumer of power that we have ever tested in that form-factor. How will the SA-ENC12G-01A perform with 8 of them?
With no disks in the system, the SA-ENC12G-01A pulls slightly more than 16W and ramps up to 106W at full load, full power. Even with a 150W power supply, there is more than enough power to spare.