Ruslan Sivak wrote:
Toby Bluhm wrote:
Ruslan Sivak wrote:
Feizhou wrote:
Ruslan Sivak wrote:
Feizhou wrote:
I do have a SIL3114 chipset, and I think it's supposed to be
supported by device mapper. When I go to rescue mode, I see it
loading the driver for SIL3112, but nothing appears under
/dev/mapper except control. Are there instructions somewhere on
getting it to use my controller's raid?
Your controller only has a bios chip. It has no raid processing
capability at all.
You need to use mdadm. anaconda should be able to let you create
to mirrors and then create a third array that stripes those md
devices,
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Anaconda doesn't let me create a stripe raid set on top of a
mirror set. And it doesn't detect it when I do it manually.
Also the bios chip presents additional issues. I believe when I
don't have a raid array set up, it won't boot at all. When I have
it on raid10, I had trouble booting, and when I have it on
concatenation, everything works fine, until a drive is replaced.
At that point, i have to recreate the array, as concatenation is
not a fault tolerant set, and at this point I seem to lose all my
data.
It won't boot at all without a raid array setup? That sounds really
funny.
Actually I'm not 100% sure on this, but I think this is the case. I
believe the first time I set it up as a raid10, assuming that linux
will just ignore it. I installed centos by putting boot on a raid1,
and root on LVM over 2 raid1 sets. I had trouble getting it to boot.
Is there a way to get it to use the raid that's part of the bios
chip?
Repeat after me. There is no raid that is part of the bios chip. It
is just a simple table.
Yes, I know this is fakeraid, aka softraid, but I was hoping that
using the drivers would make it easier to support raid 10 then with
mdadm, which seems to be impossible to get to work with the
installer. I'm not even sure why the raid10 personality is not
loaded, as it seems to have been part of the mdadm since version 1.7.
Something about device mapper?
You need the fake raid driver dmraid if you are going to set up
stuff in the bios. What version of centos are you trying to
install? libata in Centos 5 should support this without having to
resort to the ide drivers.
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I'm trying to install centos 5 - the latest. How would I go about
using dmraid and/or libata? The installer picks up the drives as
individual drives. There is a drive on the silicon image website,
but it's for RHEL4, and I couldn't get it to work. I'm open to
using md for raid, or even LVM, if it supports it. I just want to
be able to use raid10, as I can't trust raid5 anymore.
IIRC you had two out of four new disks die? So maybe it would be more
accurate to say it's your hardware you don't trust. Raid5 is used
without problems by ( I assume ) many, many people, myself included.
You could have a raid10 and still lose the whole array if two disks
that in the same mirror die at once. I guess no software in the world
can really overcome bad hardware. That's why we do backups :)
Anyway, perhaps excersizing /stressing the disks for a few days
without error would make you feel more confident about the HDs.
Actually, 2 disks did not die. Due to the fact that it was a new raid
5 array (or for whatever reason), it was rebuilding the array. One of
the drives had a media error, and this caused the whole array to be lost.
This is exactly what this article warns about:
http://www.miracleas.com/BAARF/RAID5_versus_RAID10.txt
The article doesn't seem to mention the fact that if a disk in a mirror
set dies and the remaining disk within the set starts to have data
corruption problems, the mirror will be rebuilt from corrupted data.
I don't know what you can do at this point, though. Perhaps make 2
separate mirrors and rsync them? You could keep copies of changes that
way.
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