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simple RAID 0 question that's not in the FAQ

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  • Hard Drives
  • NAS / RAID
  • Storage
Last response: in Storage
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June 21, 2004 5:40:52 PM

If you RAID 2 80GB hard disks does that essentially give you 160 GB's of storage?

More about : simple raid question faq

June 21, 2004 7:25:08 PM

Yes, Raid 0 doesn't back up your data at all, it just makes 2 or more smaller drives look like one big fatty drive.

"It's too late now anyway. That song is stuck in my head and the only way to get rid of it is to blow it out. With a bullet!! - Carl
June 21, 2004 9:45:48 PM

As obtuse said if you use RAID 0 then yes you get twice the storage and (in theory) twice the speed of a single 80G disk. If you use RAID 1 the same data is just written to both drives for security purposes, in RAID 1 2x80G disks will give you 80G storage.

<font color=blue>P4c 2.6@3.25
512Mb PC4000
2x120Gb 7200.7 in RAID0
Waterchill KT12-L30
Abit AI7
Radeon 9800Pro
</font color=blue>
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June 24, 2004 12:41:03 AM

and a slightly increased read rate? but decreased write speed?

AMD's dual-core sex fights due in 2005
June 24, 2004 8:55:04 AM

RAID 0 will in theory give you twice the read and write speed, this is only helpfull when using big files though. When you use RAID 0 and move between a lot of small files both disks have to find the file before it can be read or written to, this means you get higher average seek times than using one disk.

RAID1 - Read speeds can increase because data can be read from both disks at the same time. Write speeds are the same as using one drive.


<font color=blue>I have far too much time on my hands</font color=blue>
June 24, 2004 9:54:26 PM

<A HREF="http://www.allmediait.com/html/raid1.html" target="_new">http://www.allmediait.com/html/raid1.html&lt;/A>
Quote:
All writes must go to both drives of a mirrored pair so that the information on the drives is kept identical. However, each individual drive can perform simultaneous, independent read operations.

Mirroring thus doubles the read performance of a single non-mirrored drive

<A HREF="http://www.ahinc.com/raid.htm" target="_new">http://www.ahinc.com/raid.htm&lt;/A>
Quote:
But the offset for this is that the reading of data will realize an increase in speed.



<font color=blue>I have far too much time on my hands</font color=blue>
June 24, 2004 11:57:22 PM

Seeks are faster on a RAID 1 array than a single disk because the chances of finding info with 2 drives looking are better than just one drive looking.

s signature has been formatted to fit your scr
June 25, 2004 11:00:52 AM

To be honest there are conflicting articles on the performance advantages of RAID1, the two articles I pointed out say that it increases read speed, other articles say that it reduces latency as silverpig said.
However anandtech says in one of thier articles that only certain RAID controllers stagger the latencies. So actually you will only experience better latencies with certain RAID controllers. They dont mention anything about increased read speeds on anandtech.

<font color=blue>I have far too much time on my hands</font color=blue>
June 25, 2004 2:42:29 PM

Thanks for those links, but what I was really looking for was an article where they have actually <b>measured</b> the increase in read speed on a RAID1 array. 3ware implement an algorithim that is supposed to do this but all the measurements I have seen show that it is highly variable. I've never seen a measurement reported on another controller that shows an increase in read speed with RAID1, that's all.

<A HREF="http://www.anandtech.com/myanandtech.html?member=114979" target="_new">My PCs</A> :cool:
!