[lug] software raid

[Hugh Brown]

Thanks for the info.  The description of personalities was lacking in the
Software RAID how to (or I am blind, which is entirely possible).  I
actually read the manual before asking this time. :)

Thanks again for the description of the process.

Hugh


"Harris, James"
> 
> The personalities line does indicate that RAID is setup, but, as Sean had
> said, if you have proc/mdstat, you have software RAID support in the kernel.
> 
> Software RAID is composed of two major pieces, the low level RAID support in
> the kernel (can not be built as a module), and then each level of RAID or,
> "personalities".  These personalities are the RAID levels 0,1,4,5, and
> hybrids.  Each personality can be compiled into the kernel directly, or it
> can be built as a module.
> 
> For example, if you want to boot your system off of a mirror, then you'll
> need to compile the raid1 personality directly into the kernel (this may
> vary by distro and version of RAID, i.e. you can do it using an image and a
> module, but in my opinion it's still not truly a redundant disk system when
> you do it that way.)  This allows you to boot the root off the mirror set
> directly without having to go through the hoops of old.  Anyway, then if you
> wanted to have a large raid5 for data, you could compile the raid5
> personality as a module instead of directly into the kernel, allowing you to
> load the module before mounting the array without having to take up kernel
> space.
> 
> If you're looking for more information the Software RAID How-TO is very
> cool.  I find it very concise and easy to grasp onto.  I'd highly recommend
> checking it out.  Unfortunately either linuxdoc.org is down, or our link is
> cranky, so I can't give you a link directly to the doc, but you know where
> to find it.  ;)
> 
> Jim