[nflug] RAID

[Mark Musone]

I'd probably use software raid over most onboard SATA raid controllers..

You may also want to consider raid-5, since you'll get more usable storage
space than raid0-1

Mark


-----Original Message-----
From: nflug-bounces at nflug.org [mailto:nflug-bounces at nflug.org] On Behalf Of
Eric #4011
Sent: Friday, February 08, 2008 3:36 PM
To: nflug at nflug.org
Subject: Re: [nflug] RAID

Yes it does help, and I want to be sure I do this the right way.  The 
board is a TYAN Tomcat K8E using a Nvidia RAID controller for SATA 
drives... I have heard that the onboard RAID controllers are not that 
great, however which is better poison the Linux RAID software or the 
onboard RAID controller?

Rob Dege wrote:
>
> It's been a while since I've spoken in RAID, but I think your 
> terminology is off.  RAID-0 by default requires at least two hard 
> drives in order to configure.  The same goes for RAID 1.
>
> So, in this instance, you will use two drives to create a RAID-0 
> array.  This array now appears as a single drive.  You then create 
> another RAID-0 array using the other two disks.  This array now 
> appears as a single drive.  So now, you have two RAID0 arrays 
> independent of each other.  Finally, you create a RAID-1 mirroring 
> array, using the two RAID-0 disks that you just created.
>
> Thus, you now have a single drive, with the capacity of two drives.  
> If this is all handled within the RAID controller, linux will only 
> acknowledge the existence of this RAID-0+1 drive as a single disk.  So 
> you won't be able to use the linux software RAID to create another 
> layer of mirroring.
>
> Of course, this is assuming that your RAID controller is doing all of 
> the array structure and work.  Most of the onboard RAID controllers in 
> today's motherboards, and built shoddy.  Their contain the cheap 
> hardware, but you need to install software to configure/access the 
> onboard controller.
>
> Plus, it's been a while, but I do recall some warning about not 
> putting either the root directory or the /boot directory on a raid.  
> It has something to do about the module needed by the kernel to 
> identify the raid drive being stored on the raid drive or something 
> like that.
>
> oh well, hope this helps somewhat.
>
> -Rob
>
>
> On Feb 8, 2008 12:49 PM, Eric #4011 <eric at bootz.us 
> <mailto:eric at bootz.us>> wrote:
>
>     Hi, I was wondering if the following RAID configuration is possible?
>
>
>     I have 4 SATA drives for RAID and am using MediaShield utility to
>     configure a RAID 0+1
>
****************************************************************************
*******************
>     MediaShield States RAID 0+1 is:
>             RAID 0 drives can be mirrored using RAID 1 techniques,
>     resulting in a RAID 0+1 solution
>             for improved performance plus resiliency
>             The controller combines the performance of data striping (RAID
>     0) and the fault tolerance
>             of disk mirroring (RAID 1). Data is striped across multiple
>     drives and duplicated on
>             another set of drives.
>
****************************************************************************
*******************
>
>
>     After this I have two drives and I am ready to install
>     linux(debian etch)
>
>     My thoughts are if I also use RAID 1 software(linux) with the existing
>     two drives I will have one hard drive writing to three hard drives?
>
>     I'm wondering if this is possible?
>
>     Thank you in advance for your explanations
>
>     Thank you,
>     Eric
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>
>
>
> -- 
> -Rob
>
> Ben Franklin Quote: "They that can give up essential liberty to obtain 
> a little temporary safety deserve neither liberty nor safety."
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