[CentOS] raid 1 question
Dave Johansen
davejohansen at gmail.com
Tue Mar 12 17:28:31 UTC 2013
On Fri, Mar 8, 2013 at 6:14 AM, SilverTip257 <silvertip257 at gmail.com> wrote:
>
> On Thu, Mar 7, 2013 at 6:54 PM, Gerry Reno <greno at verizon.net> wrote:
>
> > On 03/07/2013 06:52 PM, Les Mikesell wrote:
> > > On Thu, Mar 7, 2013 at 5:40 PM, John R Pierce <pierce at hogranch.com>
> > wrote:
> > >> On 3/7/2013 3:35 PM, Gerry Reno wrote:
> > >>> Dave, I've been using software raid with every type of RedHat distro
> > RH/CentOS/Fedora for over 10 years without any
> > >>> serious difficulties. I don't quite understand the logic in all these
> > negative statements about software raid on that
> > >>> wiki page. The worst I get into is I have to boot from a bootdisk if
> > the MBR gets corrupted for any reason. No big
> > >>> deal. Just rerun grub.
> > >> have you been putting /boot on a mdraid? that's what the article is
> > >> recommending against.
> > > I've put /boot on md raid1 on a lot of machines (always drives small
> > > enough to be MBR based) and never had any problem with the partition
> > > looking enough like a native one for grub to boot it. The worst thing
> >
>
> No problems here either - I have had /boot on software raid1 on quite a few
> systems past and present.
>
>
> > > I've seen about it is that some machines change their idea of bios
> >
>
> If I do have a drive fail, I can frequently hot-remove them and hot-add the
> replacement drive to get it resyncing without powering off.
>
>
> > > disk 0 and 1 when the first one fails, so your grub setup might be
> > > wrong even after you do it on the 2nd disk - and that would be the
> > > same with/without raid. As long as you are prepared to boot from a
> > > rescue disk you can fix it easily anyway.
> > >
> > Good point, Les. Rescue disks and bootdisks are key and critical if
> > you're going to use software raid.
> >
> >
> I think we could argue that rescue disks are a necessity regardless one is
> using software raid or not. :)
Thanks for all of the helpful info, and now I have a follow on
question. I have a Dell m6500 that I've been running as a RAID 1 using
the BIOS RAID on RHEL 5. The issue is that when you switch one of the
drives, the BIOS renames the RAID and then RHEL 5 doesn't recognize it
anymore. So here are my questions:
1) Has this issue of handling the renaming been resolved in RHEL 6?
(my guess is no)
2) Would a software RAID be a better choice than using the BIOS RAID?
3) If a software RAID is the better choice, are there going to be an
impact on performance/stability/etc?
Thanks,
Dave
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