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#1 2008-12-28 00:06:19

brazzmonkey
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From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

[SOLVED] intel fakeraid matrix : dmraid issue

hello there,

i just installed arch on a system with intel fakeraid matrix (following the wiki's article).
my system consists of 2x120 Gb hard disks. an intel raid matrix is configured as follows :
- 30 Gb used for "system" (swap, /, /boot) : stripped (raid 0)
- 90 Gb used for data (1 partition for /home) : mirrored (raid 1)

my fakeraid array is properly detected upon installation. both "system" and data disks are detected, and i'm able to mount my data partition and install arch.

my computer boots properly until it tries to mount the data partition of my mirrored disk. in other words it fails to mount /home with a superblock error and asks me for root password for maintenance.

using the maintenance shell i noticed my data disk is not listed by dmraid.

what's wrong ??

does this issue come from dmraid, grub, mkinitcpio... ?

thanks for any help or guidance.

Last edited by brazzmonkey (2008-12-29 08:11:15)


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#2 2008-12-28 13:13:05

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

here's a few details so hopefully you'll help me figure out if i did something wrong :
from wiki : http://wiki.archlinux.org/index.php/Ins … _Fake-RAID

system disk (striped) /dev/mapper/isw_decajbafgg_System

/boot /dev/mapper/isw_decajbafgg_System1
swap /dev/mapper/isw_decajbafgg_System2
/ /dev/mapper/isw_decajbafgg_System3

data disk (mirrored) /dev/mapper/isw_decajbafgg_Data
/home /dev/mapper/isw_decajbafgg_Data5

upon installation, i chrooted to install grub

# dmsetup mknodes
# grub --device-map=/dev/null
grub> device (hd0) /dev/mapper/isw_decajbafgg_System
grub> geometry (hd0) 3916 255 63

3916 255 63 are C H S values i got from "cfdisk isw_decajbafgg_System"

grub> root (hd0,0)
grub> setup (hd0)
grub> quit

is there anything i forgot or misunderstood ?


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#3 2008-12-28 20:33:37

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

here's something i figured out : in order to bring my second disk back, from the maintenance shell i have to :

# mount -n -o remount,rw /
# dmsetup remove_all
# dmraid -ay
# ls -la /dev/mapper

then i can manually mount my partitions. still, that's no workaround because i don't know how to get my dmraid all my disks and partitions to be properly detected at boot time.

Last edited by brazzmonkey (2008-12-28 20:34:22)


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#4 2008-12-28 21:54:12

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

further info :
this is an x86_64 fresh install from CD.
please ask if more info is needed...


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#5 2008-12-28 23:05:05

Super Jamie
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From: Brisbane, AU
Registered: 2008-12-15
Posts: 79
Website

Re: [SOLVED] intel fakeraid matrix : dmraid issue

are you sure you want to use fakeraid? linux support for it is reportedly flaky at best

i would suggest an ext2 /boot partition, and use LVM software raid for your data. whilst i've never done tests myself, apparently this is alot faster and more reliable than fakeraid

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#6 2008-12-28 23:32:43

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

fakeraid is fine to me, i previously used it with ubuntu and opensuse with no other troubles than a slightly more difficult installation.
i haven't read anywhere that LVM software raid is any faster than built-in fakeraid... but i know these aren't as fast as hardware raid...


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#7 2008-12-29 08:10:55

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

finally, i've been able to get over this issue...
in case of using a mirrored array with dmraid, dm-mirror module is needed. it has to be listed in mkinitcpio.conf MODULES array.

i'll update the wiki article.


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#8 2008-12-31 17:18:16

fettouhi
Member
Registered: 2007-05-07
Posts: 745

Re: [SOLVED] intel fakeraid matrix : dmraid issue

Can you get grub-gfx working on your machine with dm-raid? In my case the splahimage doesn't appear at all.

Regards

André

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#9 2009-01-01 21:48:49

brazzmonkey
Member
From: between keyboard and chair
Registered: 2006-03-16
Posts: 818

Re: [SOLVED] intel fakeraid matrix : dmraid issue

fettouhi wrote:

Can you get grub-gfx working on your machine with dm-raid? In my case the splahimage doesn't appear at all.

Regards

André

Sorry André, i don't plan to use grub-gfx...


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