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Replies:
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Last Post:
Nov 18, 2007 11:35 PM
Last Post By: drazen.petrusic...
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Posts:
5
Registered:
05/26/03
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Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 2:10 AM
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We are in the process of setup of new database server. We must make a decision what is better solution for us: to use RAID 1+0 (mirror, then stripe) or to use RAID 0+1(stripe, then mirror). Can someone guide me to right decision or some white paper related to this issue?
Thanks, Drazen
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Posts:
2,343
Registered:
05/06/98
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 7:23 AM
in response to: dray
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Hi Drazen,
I go with RAID 1+0, which is the Oracle SAME standard (stripe and mirror everywhere). I have notes here:
http://www.dba-oracle.com/oracle_tips_raid_usage.htm
Hope this helps. . .
Don Burleson
Oracle Press author |
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Posts:
255
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01/10/01
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 8:11 AM
in response to: dray
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SAME, first stripe (Raid 0) and than mirror (Raid 1)
Mike Ault or Don Burleson seams confused about raid 0 and raid 1
but nevertheless first stripe
see metalink Note:406688.1
"....many types of disk storage such as EIDE or SCSI to be configured as a RAID array. Supported software RAID levels are RAID-0(striping), RAID-1 (mirroring), and RAID-5 (striping with parity) and can be implemented as part of the initial installation or through the mdadm tool set."
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Posts:
4,879
Registered:
11/27/01
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 8:11 AM
in response to: dray
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Hi,
Really, some people sometimes confuse RAID(0+1) and RAID(1+0) and think that they are the same. The performance of RAID-01 (RAID0+1) and RAID-10 (RAID1+0) are identical, but they have very different levels of data integrity. For example, RAID(0+1) flips the order of RAID(1+0). Drives are first striped, then these drives are mirrored. Typically, two or more disks are striped to create one segment and an equal number of drives are striped to form an additional segment. These two striped segments are then mirrored to create the final virtual drive. In my point of view, there is an disadvantage of this array because If you lose a drive on one side of a RAID(0+1) array, then lose another drive on the other side of that array before the first side is recovered, you will suffer complete data loss. Otherwise, RAID(1+0) which is my preference, is a stripe set made up from N mirrored pairs. Only the loss of both drives in the same mirrored pair can result in any data loss. So, recovery only involves the replacement drive and its mirror so the rest of the array performs at 100% capacity during recovery.
So, in resume, a RAID 10 (1+0) is a better choice, because in a RAID (0+1) if one disk fails you essentially, have a RAID 0 configuration. Due to the multiple disks that make up the RAID 0 segment, the probability of a disk failure is greater.
Cheers
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19,247
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 8:29 AM
in response to: burleson
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Donald,
In your article, you wrote :
Raid 0 Striping
Raid 1 Shadowing
Raid1+0 Striping and Shadowing
But Raid 1+0 is more "Shadowing and Striping", or is it Raid 0+1 ?
Nicolas.
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Posts:
4,879
Registered:
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 8:50 AM
in response to: N Gasparotto
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Hi Nicolas,
Good point.
In RAID (0+1), drives are first striped, then these drives are mirrored so, Striping and Mirroring. RAID (1+0) consists of multiple sets of mirrored drives so, Mirroring and Striping
Cheers
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Posts:
10,898
Registered:
10/08/98
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 15, 2007 10:20 AM
in response to: dray
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I found this article clearly explains the difference between RAID1+0 and RAID0+1
Why is RAID 1+0 better than RAID 0+1?
http://aput.net/~jheiss/raid10/ |
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Posts:
1
Registered:
11/15/07
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Re: Which is better: RAID 1+0 or RAID 0+1?
Posted:
Nov 18, 2007 11:35 PM
in response to: dray
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I really appreciate your answers! Kind regards, Drazen
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