300 dollars isn't much at all when you consider what the norco 4020 brings AT that cost.A Norco 4020 costs about $300. Much too much for a case.
Just do a search for 4u rackmount cases with 20-24 hot swap bays and see what you find.
The closest thing *I* could find was a supermicro case for 900 dollars, sure, it came with redundant power supplies...but let's pretend THAT costs 300 bucks (which it doesn't), you're still at 600 dollars which is twice as much. That alone makes the norco a value.
When you have big systems with 20 drives, it's not a matter of IF a drive will fail, but a matter of WHEN it will fail. Being able to replace it easily is key. Also, remember, if you have hot swap bays with lights it's much easier to SEE which drive HAS failed. Try to do that when you have 20 drives in cases without lights.
It's a pain and remember, removing the WRONG drive may cause you to lose an entire pool. accidently messing up something while your doing this can have the same result.
That is only if you store dvd quality video. When you move into 720p or bluray quality video the hours start to get smaller and smaller.20TB (20 1TB drives) of storage is at least 2000 DVDs - 4000 hours of viewing, or 20,000 hours of HDTV viewing.
Few individuals are able to view that much video.
Also, the same mentality could be used against cable tv. Are you telling me you can watch 400 channels of TV?
So why don't you go back to basic cable or OTA tv.
I'm not trying to be hostile, i'm just trying to make a point.
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I prefer to simply recycle the cases and power supplies from our home occupation. It is easy to fit enough hard drives/videos in standard case to cover all the material that will be watched more than once. And $20 hard drive external cases are sufficient for those videos that are seldom watched - no need to keep them powered up.
(I have 7 HDTV tuners recording all the TV I want and I rip 9 DVDs a week. It will take a long time to find enough material worth saving to fill up my modest disk space. And then I will never have enough time to watch it.)
But to each his own,
To each thier own. This isn't a bad method either. It all depends on what you hope to accomplish. There is no "best way" only "best compromises"