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Thread: Question about using Raid 0
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08-31-2007, 02:24 PM #1Junior Guru
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Question about using Raid 0
I'm looking at getting another server and am looking for performance. I do my own backups, and nothing on my sites is that critical where a loss of 23 hours and 59 minutes worth of realtime is going to cause the end of the world. So I'm really not looking for redundancy, just flat out performance.
Raid 0 seems to fit the bill for me as it not only uses the capacity of the drives used but increases the speed by striping the data across the drives.
So I was a bit shocked when I approached a company with my request for Raid 0 and got this response...
RAID 0 is currently not supported as part of our managed services, so if you insisted on using it the server would be unmanaged by XXXXXX XXX. I would strongly recommend against this and if you were concerned about speed, RAID 5 and 10 would be a better choice. This is my professional recommendation, however, you seem pretty insistant on RAID 0 and I will allow you to make that choice.
So what am I missing here? Is RAID 0 really all that bad?
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08-31-2007, 02:36 PM #2WHT Addict
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It doesnt just increase the risk of one drive taking out the array it DOUBLES the probability of a drive failing and therefore doubles the risk. It is just seen as a very reckless thing to do. I'd agree that RAID5 would be a better choice as if I'm not mistaken performance would be similar to RAID0 anyway with the added benefit of redundancy.
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08-31-2007, 02:37 PM #3Web Hosting Master
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Raid 0 has no redundancy. Failure of any drive results in loss of whole data and least chance of data recovery. It is less reliable, ie every drive in a RAID 0 array must be operative in order for the array to be available. There is lack of fault tolerance, which means no rapid recovery from failures is possible.
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08-31-2007, 02:56 PM #4Junior Guru
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So how does this realistically differ from having only a single hard drive in a server?
What is the percentage of hard drive failuers TOTAL? One out of 100? One out of 1,000? One out of 10,000?
Yeah everyone hears horror stories about failed hard drives, but how many people chime in with "Hey, my hard drive is running just fine!"?
Knock on wood.... in all the years I have had my own desktops, laptops, and servers, I have had only a single hard drive failure.
So is RAID 0 itself a problem, or have hard drives themselves become more cheaply made and more prone to failures to scare a server hosting provider?
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09-01-2007, 01:21 AM #5Aspiring Evangelist
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There really are not a lot of advantages to RAID0 anymore. Drives are fast enough (especially with SATA and SAS drives available) that you will only get a marginal increase in overall throughput. To gain serious speed increases you will need to go with RAID10. Disk space has also become a whole lot cheaper overall. If you need to use RAID0 to get more drive space (e.g., combining 2 160GB drives to get 320GB of space), then you probably should be using another form of RAID anyway, if only to avoid having to re-upload all of that data.
Also, drives do fail, and they fail a whole lot more than we would like to admit, especially for a datacenter. You may not have had a whole lot of drive failures, however many datacenters put up more new drives per week than you have used in your entire life. When you are dealing with those kinds of numbers, your failure rate goes up dramatically.
Using any RAID level other than RAID0 will allow a drive failure to be fixed with nothing more than a drive swap (sometimes while the machine is still online), therefore it requires much less work for the datacenter (e.g., no re-imaging, no data recovery, no emergency repairs, etc.). They are all for using anything that makes their lives easier. Why double the chances of failure with 2 drives when you can get better reliability (statistically, at least) with just one?
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09-01-2007, 09:37 PM #6Web Hosting Master
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09-02-2007, 12:33 AM #7Junior Guru
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I work at a datacenter in the Bay Area, and I'm sorry, but you may say "it's not critical", but I know when the array dies you're gonna be bugging me every ten minutes "is it back up yet? now? now?" We have a few clients like this, they don't use raid (and of course, they don't have backups) and somehow it's "our" fault when their hardware bites the dust. I'm fully with the hosting company on this one.
Go raid-10 if you really need performance, drives are insanely cheap now.