[CentOS] Software RAID vs 'fake/ on-board RAID'

Sun Feb 13 20:28:32 UTC 2011
Robert Heller <heller at deepsoft.com>

At Sun, 13 Feb 2011 13:07:09 -0800 CentOS mailing list <centos at centos.org> wrote:

> Setting:
> We are setting up a low usage server for an alfresco km/collaboration system
> It is a low-end server with a pair of 1.5 TB disks we will be mirroring
> The server comes with Intel's on-board 'fake raid/ low-end RAID' capability
> and for price reasons we have not selected a mainstream RAID card
> Prior thoughts:
> Searches on the net indicate no performance advantage, and possible
> performance disadvantages to the on-board RAID
> I expect Intel & the Centos product to be rough equivalents in quality
> I am leaning to software RAID for a simple reason of minimizing my
> administration & operational burden. If I need to perform repairs, obtain
> alerts it is the same administration toolset rather than a BIOS-based tool
> that seems to be accessible only through boot/ reboot.
> Question:
> Over a reasonable lifecycle are we better served going with the on-board or
> Centos' software RAID?
> Any issue with booting from the RAID (obviously RAID 1)?

You are always going to be better off using Linux (CentOS) software
RAID.  There are no issues with booting off a RAID 1.  You'll create
two partitions on the disks: a small one for /boot and the rest to be a
LVM volume group (carved into swap, /, and your data and/or /home). 
You'll make two RAID sets, one for /boot and the other for the LVM
volume group.  The only trickyness is to be sure to install grub on
both disks -- this lets you boot off /dev/sdb if/when /dev/sda dies.

> Thanks in advance for your thoughts.
> Dave
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Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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