[CentOS-docs] New page on installing to software RAID

Tue Apr 28 01:20:12 UTC 2009
Phil Schaffner <P.R.Schaffner at IEEE.org>

On Mon, 2009-04-27 at 21:48 +0200, Marcus Moeller wrote:
> Dear Phil,
> Sorry Phil. I personally cannot accept this HowTo at current state.

That's why I'm asking for feedback! :-)

> There is also some cute documentation available in the Deployment
> Guide.

Yes - pointed to that in the CentOS 5 FAQ entry added about the same
time as this was created.

> You wrote:
> 'Some controllers claim to be RAID but require Windows drivers to
> function, similar to winmodems.'
> This is not true. Some controllers make use of OS functionality. This
> is not dependent to Windows.

OK - agree that some such controllers may have Linux drivers.  Will note

> You wrote:
> 'Booting will only work from non-RAID or RAID1 partitions. RAID0 or
> RAID5 will not work.'
> This is only true if you wish to have the boot partition (/boot/)
> reside on a RAID parition. In this case it must be on a RAID1
> partition.

That's what I thought I was saying but obviously needs some
clarification if you read it differently.

> Also, in your scenario it does not make much sense to split /boot and
> may cause confusion, as it's not necessary on a RAID1.

Agree - addressed this point in the reply to Ned.

> You wrote:
> 'Disable any hardware-based RAID in the motherboard or RAID controller BIOS '
> Why that? I have some systems where I combine hardware- and softraids.
> This may be the case on fakeraid controllers.

OK - I know you understood what you thought I said, but what you heard
was not what I meant. :-)  Will change "hardware-based RAID" "to fake
RAID controllers without CentOS drivers".

> ...skipping...someone else could take care...
> You wrote:
> After installing a new kernel, repeat Section Three. It should be
> possible to apply a similar approach to a /boot on RAID1, or to a / on
> RAID1 without a /boot.
> Why should someone want to use dd to mirror a / partition on an active RAID1 ?

One would not.  Again apparently needs clarification.  That's why more eyes are better.