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Originally Posted by GrouchyAdmin
Not quite.
RAID0 is just 'treating it all as one disk', basically. RAID5 segments different drives (at least two) and uses another for parity. If one fails (and eventually, they all do), you can restore all of the data by the pre-existing content that is there and the parity. In the event the parity drive fails, it just rebuilds that. So, it'll take you 3 disks to make 1, but when one dies, you're only slowed down - you're not fucked.
You can't use 'two as one' as an analogy because EVERYTHING now has at least twice the amount of failure probability - two spindles, 2 controllers, (and it should be 2 different power rails, at least), etc, etc.
RAID0, if you have 2 drives, one fails - there went half the filesystem. JABOD also suffers from this, but JABOD isn't quite as bad; RAID 0 requires everything be matched up size-wize - JABOD you can just throw anything together - and unless you totally fuck up, you may be able to stitch it back together. Some filesystems can 'heal' and work better with a JABOD system - ZFS and Reiser are semi-capable of this.
At the very least, I'd suggest RAID1, where it's just a mirror of the same content spanned across two drives. One dies, hope to hell the other one isn't.
On average, RAID0 does lookup faster, and that average with 360u SCSI w/ huge cache was about 2ms. With SAS/SATA, it's probably similar. May shave 4 seconds off of the wait time for shit to load, and you just lost your life's work. What a tradeoff!
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I'm no math guy but I'm still not seeing how my analogy is so flawed.. if it's twice as likely to fail, it's half as reliable, right? If RADI0 is treating everything as one disk, could you use four as one to make it even faster? How many scsi drives would you generally need to be using to hit the wall and max out the system bus?
I think basically what you're trying to say is not to trust RAID0 for storage, right.. ? I gathered that, I'm just looking at the speed and performance aspect of it, myself..
What would it be called if you had two raid 0 arrays mirrored? That'd be a more reliable setup, right, but not necessarily "twice" as reliable, though, right?
http://www.pcper.com/article.php?aid...=expert&pid=10
These ram drives are amazing but it seems like they're even less reliable than raid 0
I don't know much about SSDs yet, need to read up on them.. but these ram drives are amazing if they provided enough storage, they'd be great to have your OS/paging file on.. If I got one I'd figure out a way to have it back itself up to something every few hours .. they have a battery backup but that still isn't too comfortable