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I have an external two-bay drive enclosure (the OWC Mercury Elite-AL Pro) connected to a Mac Mini (my home media server) over FireWire 800. I'm streaming media to other computers in the house over wired gigabit. I have two 1.5 TB drives that I'm using independently right now. The media is on one, and I'm mirroring the files to the other drive at night as a backup. But as I approach filling up the drive I'm wanting to span those two drives together to give me a total of about 3 TB, and then buy another drive for backups. The external enclosure supports both RAID 0 and JBOD, but I'm not clear on which would be better in this situation.

Would RAID 0 provide any performance improvements over JBOD for streaming video (possibly several streams at once?

How does each affect the MTBF of the drives?

In general, should I choose RAID 0, JBOD, or keep them independent?

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closed as off-topic by Tom O'Connor Aug 8 '13 at 18:56

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up vote 4 down vote accepted

RAID 0 writes into to each drive in little stripes of 64kb (or whatever size you configure), alternating drives as it goes. JBOD most commonly concatenates one disk to the other, so the beginning of the logical drive is one physical drive, and the 2nd half is the other physical drive.

Both will effect the MTBF of the array; with 2 drives you double your chances of failure (this doesn't mean half the time, that's not how probability works).

Keeping them independent means if one drive fails, you only lose the content on that drive. If it's not terribly inconvenient, I'd keep the separate. Otherwise RAID0 may have better performance than JBOD (depending on how JBOD is implemented).

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RAID0 should be quicker than just splitting your data across drives due to striping; RAID0 will load both drives more evenly - potentially working both drives harder than if split; I'd use them a separate drives, if you lose a drive you'll lose half your data, with RAID0 you'll lose all your data.

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I'd note that depending on expertise and what's being used to actually implement the RAID, in some cases the volume is hosed if one drive dies regardless of the JBOD or RAID 0 use. Chances are better you can recover data if it's a JBOD failure, but it depends on how far you want to go to try to recover the data. If he has a backup plan already set up then it doesn't really matter. RAID is supposed to give higher availability...if he's primarily reading and wants performance, he might want to google RAID level performance to decide for his case... – Bart Silverstrim Apr 30 '10 at 13:57

RAID 0 is Faster because of the nature of striping. If the Drive has larger files have a large stripe size. If the drive is to have smaller files (less than 64KB) "mainly" then use a small strip size. Most tend to use a strip size of 64KB

RAID 0 ben marks substantialy faster that a single disc. Tip is to have 2 disc of the same (ideal) or very similar in performance (cache size).

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