[CentOS] Advice on setting up Raid and LVM

Thu Mar 2 18:16:08 UTC 2006
Bowie Bailey <Bowie_Bailey at BUC.com>

Steve Huff wrote:
> On Mar 2, 2006, at 9:47 AM, Bowie Bailey wrote:
> 
> > Or you could do this:
> > 
> > RAID 1 partition:
> > md0 = 80GB (or whatever the useable total is)
> > 
> > Then include md0 in VolGroup00 and create your logical volumes.
> > 
> > LV0 = 300MB (/boot)
> > LV1 = 500MB (swap)
> > LV2 = 9.2GB (/)
> > LV3 = 70GB  (/home)
> > 
> > This way everything is mirrored and everything is in one VG.  If you
> > need more space, add another pair of mirrored drives and add the new
> > mirrored device into VolGroup00.  Then you can use the space to
> > expand whichever filesystem needs it.  I would also advise
> > following the previous poster's advice and leaving a few GB unused
> > so that you aren't forced to add more drives immediately when LV2
> > fills up faster than you expected.
> 
> i was under the impression that GRUB doesn't know how to boot from a
> logical volume, and so the configuration you describe won't work
> without a bit of tweaking, like so:
> 
> two SW RAID 1 sets:
> md0: 100MB, format as ext3, /boot
> md1: the remaining space, mark as LVM
> 
> VolGroup00:
> LV0 = 1GB swap
> LV1 = 1GB /var
> LV2 = 9.2GB /
> LV3 = some more space for whatever you need

That's a good point.  I don't know if grub will boot from it or not.
I haven't tried that on my Linux systems yet, but it is the way I do
things with my other unix boxes.

> also, does anyone know if RHEL4 has fixed the problem of GRUB only
> being installed on the first drive of a SW RAID set?  refer to this
> doc for more discussion:
> 
> http://lists.us.dell.com/pipermail/linux-poweredge/2003-July/008898.html

I remember that thread, but I don't know if there was any resolution.

-- 
Bowie