Looking For RAID Hardware/Software Advice

[Craig White]

On Mon, 2009-01-19 at 07:30 -0700, Mark Phillips wrote:
> Eric
> 
> Thanks for the summary, and thank-you to everyone for their ideas.
> 
> Based on NewEgg prices, here is some more information:
> 
> 
> Option A
> Single Disk IDE Drive - 500 GB and backups, keep OS on existing drive
> = $69.99
> Use existing controller and just add another drive. No redundancy
> 
> 
> Option B
> RAID10 with 500 GB backup capacity and redundancy, keep OS on existing
> drive = $179.97
> 2 500 GB SATA2 Drives, new SATA2 controller
> 
> 
> Option C
> RAID10 with 750 GB backup capacity and redundancy, keep OS on existing
> drive = $239.97
> Two 750 GB SATA2 Drives, new SATA2 controller
> 
> 
> Option D
> RAID5 with 1,000 GB backup capacity and redundancy, keep OS on
> existing drive = $239.97
> Three 500 GB SATA2 Drives, new SATA2 controller
> 
> 
> I am leaning towards Option C based on less power consumption with
> fewer drives. However, I have to rethink my budget...
> 
> After some more reading, I am a little confused about the debate
> between RAID5 and RIAD10. I am interested in the group's opinions on
> which is better - RAID 5 or RAID 10 and why? What experiences have you
> had regarding installation, maintenance, and fixing problems? I am
> running Debian testing.
----
http://en.wikipedia.org/wiki/RAID

RAID 10 is FAR better performance than RAID 5 - so does RAID 1.

RAID 10 in theory, requires 4 drives minimum. Think of RAID 10 as RAID 1
+ RAID 0 (hence the 10)

RAID 5 in theory, requires 3 drives minimum. 

RAID 0 = drives striped together to appear as a single drive. Logical
sectors are interleaved between the drives

RAID 1 = drives that mirror each other.

Thus a RAID 10 would have at least 2 drives striped together in RAID 0,
mirrored (RAID 1) by the same number of drives striped together.

While you might be able to create RAID 10 with only 2 drives on some
hardware, I can't think of any benefit for this over RAID 1 as the 'RAID
0' part of the array, being only single drives doesn't make much sense
and just complicates things more.

Don't know what RAID controllers you are looking at on NewEgg but be
careful of fake RAID controllers as they are cheap and common but they
don't work well...especially with Linux.

Craig