Category: Geek Bits

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RAID aware, buyer beware…

So, I was on the NewEgg site looking for external hard drive enclosures… For my mom’s new computer; yeah, um, not for me… And I found what looked like a nifty dual-drive external enclosure that has FireWire 800. It has built in RAID, which I will not be using; but I figured I would see if they had a manual on-line so I could make absolutely sure I could use the enclosure as a dual-drive no-RAID. What I found on the manufacturer’s site convinced me that I don’t want to buy their enclosure, because I can’t trust the company:

3500MGB-RAID Galaxy Series
Specifications
When it comes to raw power there is nothing to beat the dual-bay 3500 Metal Gear Box Raid. The 3500MGB-Raid is built strong and rugged, offering more than enough capacity to store all your digital media files. Not only that, the 3500MGB-Raid can also back up and secure all of your data thanks to RAID protection. Great performance, great protection and great looks – only in the 3500MGB-Raid.

Twice in the ‘specifications’ they mention the protections this device offers as a
result of its RAID technology: “the 3500MGB-Raid can also back up and secure all of your data thanks to RAID protection” and “Great performance, great protection“.

The only problem is that this device does not offer any RAID levels that provide any level of data protection! In fact, since it only supports two different modes of RAID-0, this enclosure actually increases the chance of data lost due to a drive failure. (With RAID-0 striping a single drive failure wipes out the entire array.)

They can not say that their enclosure offers any level of protection unless it provides at least RAID-1 (mirroring). And yet, they do. Which is horribly misleading and (I hope) down-right illegal under US truth in advertising laws. I can’t do business with a company that misleads its customers so blatantly.

I’ve written their sales folks, but I will be extremely surprised if I hear back.

-Chris Knight

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Hiding the problem with smoke and mirrors…

Solar shield could be quick fix for global warming – earth – 05 June 2007 – New Scientist Environment
* 15:35 05 June 2007
* NewScientist.com news service
* Catherine Brahic

A solar shield that reflects some of the Sun’s radiation back into space would cool the climate within a decade and could be a quick-fix solution to climate change, researchers say.

Because of their rapid effect, however, they should be deployed only as a last resort when “dangerous” climate change is imminent, they warn.

Solar shields are not a new idea – such “geoengineering” schemes to artificially cool the Earth’s climate are receiving growing interest, and include proposals to inject reflective aerosols into the stratosphere, deploying space-based solar reflectors and large-scale cloud seeding.

The shields are inspired by the cooling effects of large volcanic eruptions that blast sulphate particles into the stratosphere. There, the particles reflect part of the Sun’s radiation back into space, reducing the amount of heat that reaches the atmosphere, and so dampening the greenhouse effect.

The 1991 eruption of Mount Pinatubo in the Philippines cooled Earth by a few tenths of a degree for several decades.

While this idea is leaps and bounds better than venting our atmosphere into space… It does have two critical flaws:

  1. It does nothing to help that the rising CO2 levels are causing our ocean water to become more acidic, which is killing off coral reefs.
  2. In fact, the solar shield could reduce the amount of light making it to plants, adversely affecting their ability to bind Carbon from CO2 in the atmosphere. This would only aggravate the problems we already have.

Hey, try these on for size… Close the SUV loophole in the emissions laws! Consume less! Take public transportation more! Require office buildings to turn their computers, as well as their lights, off at night! There are a thousand little things that individuals and businesses can do that are easier, and make more sense, than hiding the planet behind a set of mirrors.

-Chris Knight

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200 Terabytes Served in 81 Days = 2.47TB per day!

We interrupt our regular programming with a bit of geek braggery. What? We don’t have regular programming here? Sheesh, what kind of blog is this? It’s not a blog? It’s a “Web Log”? Whatever… back to the topic at hand…

A year and a half ago the company where I was contracting decided to build a video site for gamers. It was all the rage, and they didn’t want to fall behind. The programming team was tasked with building the application, and I was tasked with designing the download systems. The manager at that time was very interested in reducing costs, and was more than happy to listen to my suggestions for a cluster of inexpensive commodity boxes that would each have a copy of the video repository on a large RAID volume and be kept in sync with rsync. I am a fan of the Google approach to colo hardware, where you build it cheap and easy to replace.

While I was out of town dealing with my father’s funeral my manager’s manager trashed all my ideas, said we were a Dell shop and were going to buy Dell gear, and he ordered two Dell servers and a cheap EMC SAN that he dictated would be our video download system. Managers who don’t know their tech should stay out of the server room. He spent $25k for an entry level SAN that couldn’t handle the sustained activity of our video download servers a mere two months after we went live. I wish he hadn’t moved on before then, because I am the sort of person to remind a manager of my original proposal and ask them to explain again why it was rejected.

Anyway… With the ‘big man’ out of the picture, and the system he mandated collapsing miserably under the load, I was able to once again pitch my idea. We did use Dell machines for the commodity boxes, but that’s because the Dell PowerEdge 1800 is a very un-Dell-like machine. Well, it was, before Dell dropped it. For around $1400 you could get a PowerEdge 1800 with dual processors, dual power supplies, and a CERC SATA RAID controller, all with a three year on-site warranty. It was a sweet deal, and unlike most Dell boxes the PowerEdge 1800 didn’t use special drive rails; so we could pack it with six Seagate 500G SATA drives fairly cheaply. Configured as RAID-5, that gave us a little under 2.5TG per server for storing videos. A simple rsync script keeps the video archives in sync after user and editor uploads. Apache 2.2 configured with the worker MPM lets me do about 600 simultaneous connections per machine before I start running out of memory. Six of these boxes behind a HAProxy load balancing system can completely saturate a 1Gbps fiber Cogent network drop with plenty of cycles to spare, and we’ve held that level of bandwidth for amazingly sustained periods of time.

For the HAProxy box I used a Dell PowerEdge 2850 with PCIe slots. In order to make the most of our bandwidth I used an Intel PCIe 4x Gigabit Fiber card for the cogent drop and Intel PCIe 4x Gigabit Copper card for the server side. The load balancer and six servers were connected via a Cisco Gig-E switch.

In the past 81 days we have served 200 Terabytes from this little server cluster that I designed and built on a tight budget. I think that is cool. 🙂

-Chris Knight

I use Amazon affiliate links in some of my posts. I think it is fair to say my writing is not influenced by the $0.40 I earned in 2022.