Mirror Mirror

[Rick Stevens]

Scott Mertens wrote:
> With these SATA drives as cheap as they are I am thinking about just
> purchasing another 200 GIG HD and setting up a mirror in Linux.
> 
> 
> My thinking is that if one drives fails, I can simply break the mirror,
> switch SATA hard drive cables - re-boot and away I go.
> 
> I am using 
> Red Hat Enterprise Linux ES release 4 (Nahant)
> 
> Can anyone tel me if this is possible, or do I have my head way up
> my ???  Is this something Linux can do out of the box, or is there some
> add-on's I need to accomplish.

It is certainly doable by either hardware or software.  You're talking
about RAID-1 (disk mirroring).  Most SATA controllers are capable of
doing it, but usually need the help of the OS to accomplish it.

Linux has software RAID (called "md" for "multiple devices").  grub
has support for booting software RAID volumes.  I'd recommend you
go off and check out the Software RAID HOWTO at:

	http://www.tldp.org/HOWTO/Software-RAID-HOWTO.html

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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
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-                 IGNORE that man behind the keyboard!               -
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