do you have a faster array using raid0+1 or raid1+0?

2011/1/31 Roberto Spadim [off-list ref]:

hum that's right,
but not 'increase' (only if you compare raid0+1 betwen raid1+0) using
raid1 and after raid0 have LESS point of fail between raid 0 and after
raid 1, since the number of point of fail is proportional to number of
raid1 devices.

2011/1/31 Robin Hill [off-list ref]:

quoted

On Mon Jan 31, 2011 at 01:00:13PM -0200, Roberto Spadim wrote:

quoted

i think make two very big raid 0
and after raid1
is better

Not really - you increase the failure risk doing this.  With this setup,
a single drive failure from each RAID0 array will lose you the entire
array.  With the reverse (RAID0 over RAID1) then you require both drives
in the RAID1 to fail in order to lose the array.  Of course, with a 4
drive array then the risk is the same (33% with 2 drive failures) but
with a 6 drive array it changes to 60% for RAID1 over RAID0 versus 20%
for RAID0 over RAID1.

Cheers,
   Robin
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Roberto Spadim
Spadim Technology / SPAEmpresarial

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Roberto Spadim
Spadim Technology / SPAEmpresarial
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