Booting from ATA100 Raid

[alvin at Mail.Linux-Consulting.com]

hi all

my opinions...

i think raid is good to protect against disk failures
or bad partitions ...

large data storage should be on raid5...

system disk should NOT be on the same disk as the "large irreplaceable
data disks"...

system disk is already backed up on the cdrom from which you
installed ... or can copy from other similar servers

most motherboards come with two ide controllers so you
can have dual system disks ( mirrored ) to boot off either disk

if booting or system disk crash is an issue....
	use root raid on two mirror'd drives

	-
	- i just built a raid1 ( mirror ) root-raid box...
	- works out of the box ( rh-7.1 )
	-
	- unplugged /dev/hda   and booted fine off of /dev/hdb
	- ( redhat-7.1 restriction for where to put the mirror )
	-
	- but it does boot in degraded mode so you should recover
	- what you need and shutdown immediately and rebuild or
	- resync your new system disk back into the raid mirror
	-
	- i would NOT put the "system disk" on the same
	disks as its data... if one disk goes bad...you lose both
	system and data...
		- you wanna be able to recover your data..
		- replace the system disk and you're back and running

- getting IDE drives on the same bacle to perform like it was scsi-3
  disks is alot harder to do... guess thats why scsi drives are 
  more expensive ??

have fun raiding
alvin
http://www.Linux-1U.net - 500Gb 1U Raid5 ...
http://www.Linux-Sec.net - firewalls - monitoring - etc 


On Wed, 9 May 2001, Greg Lindahl wrote: 
> On Wed, May 09, 2001 at 12:46:48PM -0400, Worsham, Michael A. wrote:
> 
> > Perhaps you should look at having a primary drive (ie. hdc) as a boot device
> > then running the RAID that way off of it. 
> > I mean you really don't want to ever boot up in RAID already since its more
> > for your data storage and application, rather than running your kernel on it
> > directly. 
> 
> One use for RAID is for your system disk, which is a single point of
> failure for the entire cluster on a Beowulf2 system. It's not hard to
> get a small 2-disk RAID card (3ware or promise) for this purpose.
> 
> -- g
> 
> 
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