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Questions to ask before purchasing an Array

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Royce Hildreth
Questions to ask before purchasing an Array
on Dec 18, 2010 at 1:53:39 am

Hey everyone,
I'm looking into getting a new 4 maybe 8 slot array and config as Raid 5 or 6.

I produce, shoot, edit lots of corp stuff and broadcast commercials, decent amount of 2d motion graphics. Current work flow is shooting P2 720p, some DSLR, and editing on 8-core (2x3GHz Quad-core Intel Xeon), 6GB ram. Editing off lots (26, yes 26) LaCie's and 2 CalDigit S2VR's. None of my externals are raided together. My current backup is an eSATA enclosure that I feed raw drives.

Sometime early/mid next year I will be purchasing another camera, perhaps Pani AF100 or DSLR route. I'm also considering the AJA Ki Pro mini.

Before I upgrade camera I need/want to get a better/faster storage solution. Something that will work well with P2, h264, Pro Res HQ-LT. I have been looking into CalDigit, Sonnet and G-Tech and have read quite a bit. However I was wondering if any of you would mind sharing what you looked for in a RAID 5 or 6 and why? Maybe what you think I should look for? Aside from the obvious of speed (SAS connection), price, types of drives inside enclosure, customer support. A couple things I'm considering includes; warranty, rebuild time if a drive fails, if an enclosure or raid card fails am I able to remove drives in the bad enclosure and populate a new enclosure or switch out raid card without disturbing media?

Your thoughts, input and/or answers to my questions are greatly appreciated

Thanks
Royce
rhildreth@hildrethmedia.com
http://www.hildrethmedia.com


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Bob Zelin
Re: Questions to ask before purchasing an Array
on Dec 18, 2010 at 4:10:26 pm

your question confuses me. You have mentioned three excellent manufacturers. Guess what - all the companies that advertise on Creative Cow make teriffic drive arrays. They all work, they all auto rebuild, they all cost a lot of money.

Now, let me tell you what you didn't ask - can you go to Newegg or Other World Computing or another cheapo mail order company, and buy the same quaility drive array for a lot less money, and still get away with it - NO, you can't.

Since Creative Cow has forums for all the good manufacturers, you can read these forums, and see the kind of response each manufacturer has, and what clients of these companies think.

SO, which one do I personally like - I can only tell you what I don't like - when you see a RAID array that will cost $4000, and you see the equivalent array on a "mail order" site for $900 - do you actually think you are getting the same thing ?



Bob Zelin



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Royce Hildreth
Re: Questions to ask before purchasing an Array
on Dec 20, 2010 at 7:43:50 pm

Bob and others,
Yes I know CalDigit, Sonney and G-Tech make great products and I understand that I will be spending $4000 or more on my solution. My challenge is to find what I feel is the best for my needs and workflow. Of course each of the arrays do basically the same thing but some do certain thing better, faster, etc. Yes they all rebuild but why can't I find how fast they build and the performance loss while rebuilding? It's important for me to know if an enclosure or raid card fails, am I able to remove drives in the bad enclosure and populate a new enclosure or switch out raid card without disturbing media?

I'm pretty knowledgeable about what I want in a camera and why, but RAID storage is new to me. With some of your experience I was curious if there are certain things some of you would be looking into if you were about to purchase?

Thanks again



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Bob Zelin
Re: Questions to ask before purchasing an Array
on Dec 20, 2010 at 8:46:45 pm

Hi -
I am very familiar with both Maxx Digital and Sonnet drive arrays, as they both use the ATTO R380 host adaptor card. Their rebuild time is ALL DAY LONG. When you have a drive failure, it is my advice that you continue to work, and before you go home, you pop in the replacement drive, and the rebuild will be done by the time you come in the next morning. The rebuilt time varies depending on the size of the drive. I have recently rebuilt a Cal digit with a failed drive, and it was still going by the end of the day. When we came back in the next morning, the rebuild was done, and everything was fine. I personally do not feel that it is that important to find out if the rebuild time of a Cal Digit is 1 hour faster than the rebuild time of a Sonnet (for example).

All of these products do over 450MB/sec (most do 600 - 700 MB/sec) so with a failure, you are only losing about 100 - 150Mb/sec, which means that you can STILL playout uncompressed HD even with a failed drive.

You have mentioned all great companies. So, how do you choose - some people choose by price, others choose by CALLING THE COMPANY, and seeing how quickly they can get a support person on the line.

Bob Zelin



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John Heagy
Re: Questions to ask before purchasing an Array
on Dec 27, 2010 at 2:00:04 am

With 2TB drives, soon 3TB, and all day rebuild times, RAID 6 is something to consider. Are you okay hoping a 2nd drive doesn't fail during a 14hr rebuild on a RAID 5 array?


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Steve Modica
Re: Questions to ask before purchasing an Array
on Dec 29, 2010 at 8:45:32 pm

If you are using more than 10drives, you should definitely be raid6.

There are two things to look for in a raid vendor:

1. Do they talk to you in guaranteed stream count or MB/sec? If it's the latter, they probably don't understand the difference between average performance and realtime frame delivery. Who knows what else they don't understand? That's not FUD. People will build something and claim it works because the plugs fit together. :( We get these calls all the time.

2. Do they understand the Mac kernel? If not, how can they support you when something fails? Can they instrument the kernel and profile the IO activity? Do they know how to spot a "hot lock" that might be slowing you down? No.. They don't. We write out own drivers and deploy our own firmware on the hardware we sell. We absolutely understand this stuff.

I'll wager that outside of Apple, only Small Tree can do this, because we supported realtime stuff like this for SGI for the military and NASA. Even better, our stuff is less expensive than most of the other stuff out there. We don't have to build anything fancy, we just know how it works!

Be especially careful as you wade into 6Gb SAS and 10Gb ethernet. These are new technologies and I haven't seen a single piece on my desk that worked correctly out of the box. So there's a lot of caveats to putting something like that together.

Steve


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Eric Cox
Re: Questions to ask before purchasing an Array
on Jan 11, 2011 at 7:44:23 am

Ultimately, you are not just purchasing hardware from a prefab shop, but rather you are purchasing a support contract.

If you have to ask the question of why should I buy one of these guys and not build it for half the cost then you probably shouldn't be building it.

For me I could very well build a very large array, make it fast and be quite capable of troubleshooting it if there are issues. (I do it all the time with in house farms and vendor gear) What I cannot do is guarantee that the components won't work bug free out of the box. In fact, without a lengthy test cycle or simply recycling someone elses design there can be any number of issues. Even recycling the core components of a known design it's not guaranteed to have some random devastating bug crop up weeks later that might corrupt random data. (Hello HP drive cache bug) To be honest, if you don't have a very close relationship with the vendor you are only going to hit front line support which is composed mostly from zombies and shrubberies.

While at first glance it might seem storage vendors are the sum of the hardware they provide this is in actuality not even remotely close to their best offerings.

Now that said... these things are only as important as your data so if you can afford to lose it then goto town. It's a fun and exciting world in the storage world, but do be prepared to spend some late nights learning.


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