View Full Version : RAID cards

11-04-2005, 09:33 PM
Hey guys, long time regular lurker, limit micro regular, first time CTH poster.

A coworker suggested to me an interesting trick that I've never used before: instead of buying a large hard drive, he always buys two smaller ones and a cheapo RAID0 card.

Because of the nonlinearily in prices, for the same cost he gets about the same hard drive space, much better HD access speed since he has twice the heads, and frees up both IDE ports so he gets maximum throughput on his optical drives.

But it seems like if this idea was flawless, then everyone would be doing it. I'm trying to think of a good reason why this idea isn't more popular. Apart from the slightly greater setup complexity (which isn't a big deal), and the slightly decreased reliability because you only need 1 of 2 drives to fail (which shouldn't be a problem unless you're using the hard drives for a fairly long time period), I don't see any disadvantages. Can anyone provide me with any oher downsides to this setup?

11-04-2005, 09:41 PM
Raid 0 setups are much more likely to fail than normal setups. Not that it'll fail often, but it does occur somewhat more often than usually. One thing is that only one HD needs to fail, but the raid controller might also fail, in which case the whole raid setup also fails. Also, if the raid fails, you will not be able to recover any data, whereas on normal setups that have failed, you're normally able to recover somewhat of the data.

I really won't recommend Raid0 to any "normal" users unless they can come up with a good explanation for needing the extra speed. If you do need the speed, i'd recommend that you get either a raid 0+1 or raid 5.

Raid 5 gives you slightly better performance than normal setups, though not as fast as raid 0. Raid 5 can be recovered though, it can continue running even if one disk has failed. If two disks fails, you're fubar.

EDIT: Oh yeah, and if you're wondering about the different raid setups, here's an easy to understand graph:


11-04-2005, 09:49 PM
hahaha, that's a great explanation.

no content to add, that just needed a comment.

11-04-2005, 11:32 PM
striping doesn't improve access speed, it improves sustained transfer rates. those matter in large, completely linear read/write situations (like opening a 2gb file, copying a 2gb file, that sort of thing) - not typical (even multitasking) use. as already mentioned, it is a big threat to your data because the loss of just one drive will hose you.

see http://faq.storagereview.com/tiki-index.php?page=SingleDriveVsRaid0

11-05-2005, 12:50 PM
I have a RAID 0 installed in my computer and got complacent with backing up my data. When several capacitors on my motherboard went bad, those drives were essentially useless. I had to search long and hard to get the same motherboard since it had an integrated RAID controller. I was able to rebuild the array, but it took weeks. I have all my data back, but I got lucky. If you plan to use the RAID for data you can afford to lose (like music that is backed up on DVDs) the go ahead and do it. Otherwise, it is not worth the risk since a whole slew of things could go wrong that you don't even know is possible until it's too late. Big hard drives are pretty cheap anyway... I found a new 160 gig Seagate 7200 RPM with 2mb cache for 29.95 at a Best Buy sale a couple months ago.