[windows2000] Re: Hardware Raid question

  • From: "Sullivan, Glenn" <GSullivan@xxxxxxxxxxxxxx>
  • To: <windows2000@xxxxxxxxxxxxx>
  • Date: Tue, 3 Oct 2006 15:31:45 -0400

D'oh...
 
The third paragraph should read:
Raid 10 is a stripe set with no parity (RAID 0) which is not normally
redundant.  But in this case, each drive in the stripe set has a mirror.
So a RAID 0 of three drives becomes RAID 10 when you mirror each one of
those three drives to another drive.  So essentially, you use 50% of
your drive space for Fault Tolerance.
 

Glenn Sullivan, MCSE+I MCDBA
David Clark Company Inc. 

 

________________________________

From: windows2000-bounce@xxxxxxxxxxxxx
[mailto:windows2000-bounce@xxxxxxxxxxxxx] On Behalf Of Sullivan, Glenn
Posted At: Tuesday, October 03, 2006 2:05 PM
Posted To: Windows 2000
Conversation: [windows2000] Hardware Raid question
Subject: [windows2000] Re: Hardware Raid question


They are the same.
 
If you are referring to 0+1 vs. 10, there is a fairly major difference.
 
Raid 10 is a stripe set with no parity (RAID 0) which is not normally
redundant.  But in this case, each drive in the stripe set has a mirror.
So a RAID 0 of three drives becomes RAID 0+1 when you mirror each one of
those three drives to another drive.  So essentially, you use 50% of
your drive space for Fault Tolerance.
 
RAID 0+1 is the opposite... it is a mirror of two stripe sets.  So you
start with two RAID 0 stripe sets of the same size, and then you mirror
from one set to the other.  You end up with two identical "sets" of
data, but probably no two identical "drives" of data.  You also
sacrifice 50% of the drive space to FT.
 
RAID 10 is far more fault tolerant than 0+1 though... in 0+1, if a
single drive fails, the entire drive set fails, hence one image of the
Mirror fails, and there goes your FT... You are left with a single,
non-FT RAID 0 array.
 
a RAID 10 array can handle up to half of the drives failing, as long as
they are the "correct" half.  For each "drive" in the overall RAID 0
stripe set you have two copies, so you can afford to lose one of each
mirror pair, and the RAID 0 set will still function.
 
Boiled down, RAID 10 is a stripe set made up of mirrors, RAID 0+1 is a
mirror set made up of stripes.
 
Confusing as hell,

Glenn Sullivan, MCSE+I MCDBA
David Clark Company Inc. 

 

________________________________

From: windows2000-bounce@xxxxxxxxxxxxx
[mailto:windows2000-bounce@xxxxxxxxxxxxx] On Behalf Of Beckett, William
(Bill)
Posted At: Tuesday, October 03, 2006 11:20 AM
Posted To: Windows 2000
Conversation: Hardware Raid question
Subject: [windows2000] Hardware Raid question



Can one of you hardware/RAID gurus explain the suttle differences
between Raid 1+0 and Raid 10? 

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