[windows2000] Re: Hardware Raid question

  • From: "Sorin Srbu" <sorin.srbu@xxxxxxxxxxxxx>
  • To: <windows2000@xxxxxxxxxxxxx>
  • Date: Wed, 4 Oct 2006 08:48:33 +0200

Confusing? Hell yeah! When I first read your description I had the impression
it was the same thing, but checking the ac&nc-link earlier gave another
picture on this. Now I understand what you mean! ;-)
 
I didn't ask the initial question, but find everything-raid highly amusing, as
long as I don't have to trouble-shoot it, especially the higher-level raids.
8-)
 

  _____  

From: windows2000-bounce@xxxxxxxxxxxxx
[mailto:windows2000-bounce@xxxxxxxxxxxxx] On Behalf Of Sullivan, Glenn
Sent: Tuesday, October 03, 2006 8:05 PM
To: windows2000@xxxxxxxxxxxxx
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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