[NTLUG:Discuss] Dell Server with PERC RAID

[Neil Aggarwal]

Chris:

I looked at the referenced articles and I don't see what the 
difference is between RAID 0+1 and RAID 10.

Can you please clarify?

Thanks,
	Neil


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Neil Aggarwal, JAMM Consulting, (972)612-6056, www.JAMMConsulting.com
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> -----Original Message-----
> From: discuss-bounces at ntlug.org 
> [mailto:discuss-bounces at ntlug.org] On Behalf Of Chris Cox
> Sent: Friday, September 26, 2003 10:08 AM
> To: NTLUG Discussion List
> Subject: Re: [NTLUG:Discuss] Dell Server with PERC RAID
> 
> 
> Cameron, Thomas wrote:
> > RAID 0+1 (often called RAID 10) is two RAID 0 arrays which are
>  > mirrored (RAID 1).  Gives you the benefit of fast striping
>  > plus the fault tolerance of mirroring.  It's just ghastly 
> expensive.
> 
> Actually RAID0+1 and RAID10 are radically different things.
> http://www.acnc.com/04_01_10.html
> http://www.lsilogic.com/products/stor_prod/raid/backgrounder1.html
> 
> Low end RAID controllers do 0+1 (it's easier to handle).  RAID 10 is
> a highly reliable RAID, RAID 0+1 isn't.  You'll only find RAID 10
> on your high end controllers (e.g. a MegaRAID Elite 1600 can do
> RAID 10, perhaps a bit old, but works well with Linux).
> 
> Since disk has become cheap, creation of RAID 10's is now
> quite practical (remember 4G drives used to cost $3000).
> On systems where it works right you get the performance of
> RAID0 with the reliability of RAID1 AND.. unlike RAID0+1,
> you can more than one drive failure (depends on location and
> number of columns though).
> 
> RAID10 is considered the creme de la creme of RAID (but
> probably the most expensive RAID config... but practical
> considering today's disk prices).  You may have to pay
> to get a controller and setup that supports RAID10 though.
> 
> If you need HIGH reliability and FAST reads/writes...
> RAID10 might be a viable choice for you.  Most roll
> the dice and use good quality SCSI and run RAID0+1
> though (mostly because of limitations in their choice
> of RAID controller though).  Or run just RAID1 or
> run RAID5 (slow writes and slow rebuilds).
> 
> The web links above do a pretty good job showing
> the differences between the various RAID levels.
> 
> 
> 
> 
> 
> 
> 
> 
> 
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