[CentOS] Re: Raid5 issues

Fri May 4 14:09:02 UTC 2007
Ruslan Sivak <rsivak at istandfor.com>

Feizhou wrote:
>>>> 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.
>
> I don't know about a raid10 personality but on boxes I used to run, I 
> had raid1 and raid0 personalities loaded...

According to this, as well as other sources, the raid10 personality 
should be in the kernel by now:
http://cgi.cse.unsw.edu.au/~neilb/01093607424

I do have raid1 and raid0 personalities, but I can't seem to combine 
them in the way that the installer would let me install on it. 

I did
2 drives in md11 as raid1
2 drives in md12 as raid1
md11 and md12 in md10 as raid0

Anaconda only sees md11 and md12

I can set up LVM on top of md11 and md12.  Is that really raid10 though?
>>>> 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.
>>> _________________________________
>> 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.
>
> There you go. The installer picks up the drives individually so the 
> installation process treats them as such but the raid bios does not 
> and so leads to booting problems. Just blow the raid array configured 
> in the  si311x bios the thing should be able to boot. Check also your 
> motherboard bios settings too.
> _______________________________________________

I will try this.  I do know it loads up the SIL3112 driver during the 
installation process.  Is this only so it can read the drives?  I though 
the whole process was transparent and didn't need special drivers if 
it's just seeing them as single drives? 

Russ