CentOS docs - Apr 2009 - New page on installing to software RAID

http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5

Comments and corrections please.

Phil Schaffner wrote:
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
> 
> Comments and corrections please.
Hi Phil,

Was just looking at this earlier.

Wouldn't it be a lot simpler to put /boot on raid1 too - wouldn't that 
save the lengthy process of manually duplicating those partitions? Then 
only grub would need manual installation onto the second drive's mbr.

My understanding is that GRUB/Lilo have no issue with an ext3 /boot 
partition being located on software raid1.

By not placing /boot on raid1, doesn't it just make the whole process a 
lot more complicated than it needs to be?

I realise that in this instance, this document addresses a specific 
issue this user is having due to /boot not being on raid1. But if we're 
going to have a doc that describes how best to set up software raid1 at 
installation...

/disclaimer - I'm definitely not a raid expert!

Cheers,

Ned

Dear Phil,
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
>
> Comments and corrections please.
Sorry Phil. I personally cannot accept this HowTo at current state.
There is also some cute documentation available in the Deployment
Guide.

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.

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.
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.

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.

...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 ?

Best Regards
Marcus
Best Regards
Marcus

On Mon, 2009-04-27 at 14:53 -0400, Phil Schaffner wrote:
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
---\
"After installing a new kernel, repeat Section Three."

That has got to be BS. There has to be a better way and easier way. I
just read the article. I need to think on that one. I have never heard
of that.

What happen to using "mdadm" instead of dd?

JohnStanley

They do not work!!!!!

Vlad.mobile

On Apr 27, 2009, at 16:50, donavan nelson <donavan at centos.org> wrote:

dnk wrote:
Instructions at the bottom of every email.

Go to:
http://lists.centos.org/mailman/listinfo/centos-docs


d

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On 27-Apr-09, at 2:59 PM, Vladimir Freidin wrote:

how do i remove from your emails!
i subscribed ti an email forums without knowing that.
i am sick of zillion emails here about crap!


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That is EXPECTING much more than some people are capable of.  Even with 
screen shots, flashing arrows, crayons, and sippy cups.

..dn
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Phil Schaffner wrote:
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
> 
> Comments and corrections please.
Well done on taking this up, you will find everyone has a different 
opinion on this, but try and stay as close to the upstream docs as 
possible. I'd even say this is a good article that can benefit from 
screenshots from the installer.

Perhaps what we need is a complete section in the howto's page that 
talks about storage devices and management of these ( need better phrase ).

Also, a _lot_ of content on this subject matter including mdraid/real 
raid/lvm/iscsi is covered in the upstream docs, which are also published 
at www.centos.org/docs/ so pointing to relevant sections in those docs 
would be nice.

- KB

Phil Schaffner wrote:
> http://wiki.centos.org/HowTos/SoftwareRAIDonCentOS5
> 
> Comments and corrections please.
I dont understand what this line means:

"This page created and maintained by PhilSchaffner. Other Wiki 
contributors are invited to make corrections or additions. "

What makes you think that other pages in wiki.centos.org will not allow 
other wiki contributors to make edits ? And you cant make edits unless 
there are edit rights for a page ( at this time ), so the idea of a 
'wiki contributor' is a bit strange to me.

Finally, will you not accept contributions from people who might not 
have wiki edit rights ( and therefore not 'wiki contributors' )

- KB