RAID and JBOD Questions

[dafoe]

I am looking to create a media center of sorts. I want to put everything I have on DVDs onto external hard drives. Some of it will be DVDs, avis and divx files which I will play through my Popcorn Hour by connecting the hard drives to my PC and using the PH USB wireless device. The rest will be photos and other data which only be accessed through the PC/

I started out a few days ago with a 2tb WD external and have started transfering stuff to it. I am not going to buy all the hard drives at once since the price of hard drives falls so quickly. I don't want to click through 6 or 7 different hard drives just to find what I want. It would be an organizational nightmare.

So, what I want to do is build one big hard drive through RAID or JBOD that i can easily add to as needed. This is essential. I need to be able to add hard drives without having to reformat the whole setup.

The problem is, I know nothing about RAID- I've never dealt with it before. Is there a version of RAID or JBOD that will allow me to do what I want? Also, what happens if I lose my operating system or need to move them to another PC?

If anybody could help me through the proccess, I would really appreciate it. Thanks.

[redwudz]

I have about 25 HDDs on my three servers, but no RAID. I keep the HDDs sizes to 500GB, so if I lose a drive I don't lose that much data. And since most of the video on my HDDs is from DVD and BD discs, I can replace it easily enough. I don't have any problem finding a particular video. I use a catalog program that does the searching and organizing, Extreme Movie Manager. http://www.binaryworks.it/extrememoviemanager/

I access it all over a gigabit LAN. The servers are only turned on when I want to access them. Saves energy and wear.

But if you are interested in a RAID system, you will likely need at least four HDDs for redundancy, and a controller that can handle them. The controller is the weak point. If it fails, nothing works, so it pays to use a good brand, maybe Promise or Adaptec or similar.

For basic RAID info, look here: http://en.wikipedia.org/wiki/RAID

[lordsmurf]

RAID 0 (and JBOD) are abusive to disks. You don't need RAID for amateur video, including a media center. It won't speed you up.

In fact, RAID 0 fragmentation makes it slower than an optimized SATA.

You can't just add drives.

[rallynavvie]

If you're talking about RAID over several separate USB drives forget it. That would mean software RAID on the host device and you are not going to like the results.

You can buy multi-drive external USB, eSATA, or FireWire enclosures which support some RAID levels and that's probably your best bet. JBOD allows you to make a single, large volume from several disks and you can add more to the array to make the volume larger. The problem with JBOD is, depending on the controller, a file might span two (or more) drives so if one of those goes then that file will be incomplete.

I have a 24-drive storage array that I use for DVD ISOs (so I don't have to take my DVD collection back and forth between home/cabin) but instead of using JBOD to make all the drives appear as one I use the file server OS (in this case an old Ubuntu build) to access all the drives and serve them to the network as a single share. That way if a single drive fails I only lose what's on that drive an nothing that may be spanning drives. This has been an ideal solution for me so far.

As some have already said you don't want to go down the path of any of the other RAID levels because you do not need that sort of sustained I/O for media playback. Single drive performance is more than enough for this sort of use. My storage array hosts ISOs which are mounted as DVDs on a networked HTPC just fine like that.