[CentOS] Re: Raid5 issues

Sat May 5 03:18:32 UTC 2007
Feizhou <feizhou at graffiti.net>

>> 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?

Striping of two mirrors via lvm is technically the same.

>> 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?


The problem here is that Linux uses the disks differently from what the 
bios expects. When the drives are treated individually, things are 
written to disk in a different manner than from when dm is in use. 
Besides, I do not remember there being any ability to boot of a fakeraid 
  array. grub certainly does not know how to interpret things the way 
the bios says things should be. Please just destroy that array setup in 
the bios if you plan to boot off disks on the si3112.