Install problem with 2.6.3 and RAID0

shrub · n00b Joined: 04 Mar 2004 Posts: 8

Hi guys,

I'm having a bit of a problem installing gentoo onto a setup including software RAID0.

After the installation via Knoppix, Grub loads fine and then starts to boot the system until I get this error message:

md: Autodetecting RAID arrays.
md: autorun...
md: ...autorun DONE.
EXT3-fs: unable to read superblock
EXT2-fs: unable to read superblock
FAT: unable to read boot sector
VFS: Cannot open root device "md0" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic: VFS: Unable to mount root fs on unknown-block(0,0)

I have setup my system as follows:

raidtab:

raiddev /dev/md0
raid-level 0
nr-raid-disks 2
chunk-size 32
persistent-superblock 1
device /dev/hda2
raid-disk 0
device /dev/hdb2
raid-disk 1

fstab:

/dev/hda1 /boot ext2 noauto,noatime 1 1
/dev/md0 / ext2 noatime 0 0
/dev/hdb1 none swap defaults,pri=1 0 0
/dev/cdroms/cdrom0 /mnt/cdrom iso9660 noauto,ro 0 0
none /proc proc defaults 0 0
none /dev/shm tmpfs defaults 0 0

grub.conf:

timeout 10
default 0
fallback 1
splashimage=(hd0,0)/grub/splash.xpm.gz

# Gentoo 2.6.3-gentoo-r1
title Gentoo Linux 2.6.3-gentoo-r1
root (hd0,0)
kernel (hd0,0)/linux-2.6.3-gentoo-r1 root=/dev/md0

HELP!!!!
I am at work at the mo but when I get home I will try changing the root= to /dev/md/0 and also the same in fstab as other users of this forum have suggested that but not always with the desired results which is why I am fishing for any more ideas in case this doesn't work

I noticed another post that had exactly the same problem and they solved it by loading his off-board IDE controller drivers into the kernel (which he says enabled the kernel to see his hard drives) but I can't understand how my system could boot GRUB and then start loading the kernel if it can't access my harddrives - any ideas?

BTW, I am using an Intel ICH5R S-ATA chipset to control my drives but haven RAID functionality dissabled in the BIOS. My drives are S-ATA WD Raptors (not that this should really make any difference).

Thanls in advance and sorry for the long post!

cyrillic

shrub · n00b Joined: 04 Mar 2004 Posts: 8

I have just been finding it hard to get my head around how GRUB can be loaded from my bootsector (and harddrive for the config file and splash etc) and then my kernel executed from my /boot partition when there are no SATA drivers loaded for my motherboard chipset and ALL of my harddrives are connected to this.

I can happily report though that compiling the kernel with SCSI support (including low level SATA ICH5 support) solved the problem of not being able to access the root partition. Would the drivers have been required if the root partition was not RAID0 (as with the /boot partition) and if so why?

The boot process fails now just after the Gentoo coloured text wizzes by and RAID devives are being initialised. device 0 is just being initialised and the process dies. Could this be because I compiled support for the Intal IIP? RAID device into the kernel (thinking this might support the ICH5R even though I had read that support for this software RAID solution would not be supported).

Thanks again in advance

Just had another thought actually:

Maybe the problem lies in the fact that when GRUB autodetects my RAID0 array during boot it assigns it to /dev/md0 but in my fstab and raidtab files I refer to the array as /dev/md/0. When I get back to my PC on monday (the wait is killing me) I will try editing these files and see what the result is. If it is still a no-go I will chroot into my install from Knoppix and recompile the kernel without PIIX RAID support and give that a wurl.

Any more suggestions are more than welcome (hint, hint).

BlinkEye · Posted: Sat Mar 06, 2004 6:50 pm Post subject:

hmm. i'm struggling with the same/a similar problem. it can't mount my boot device "md1", hence a kernel panic. please keep us up to date if you get any further

shrub · n00b Joined: 04 Mar 2004 Posts: 8

Problem solved!

I simply changed the device name of my RAID array from /dev/md/0 to /dev/md0 in fstab and raidtab and everything now works fine.

Just need to get my NIC working properly now...

BlinkEye · Posted: Tue Mar 09, 2004 5:26 pm Post subject:

so did i https://forums.gentoo.org/viewtopic.php?t=145852&highlight=

DancesWithWords · Posted: Tue Apr 13, 2004 9:04 pm Post subject:

Just an addendum, after about a week of reading this forum and googling I've managed to get my IDE Highpoint Raid 370/372 working and then tried to extend my experience to getting Linux Software Raid working.

What I learnt from the experience was;

1. IDE Highpoint Raid 370/372 would not work with 2.6.5-rc1. This was stated in many posts and if it does work I did not find the solution.

2. I did get the IDE Highpoint Raid 370/372 to work with ck-sources 2.4.23, but it only worked if the option was built into the kernel. I never could get it to pickup the raid, if the option was enabled as a module.

3. In order for Linux Software Raid to work reading the Howto's was very useful, but for one fact. To get Raid to work I had to use fdisk and change every partition to type "fd" 'Auto Detect Raid" in my raid. I did not find this spelt out clearly in anyones doc's or Howto's.

So my configuration looks like this
==============
RAIDTAB

raiddev /dev/md0
raid-level 0
nr-raid-disks 4
chunk-size 32
device /dev/hda3
raid-disk 0
device /dev/hdc3
raid-disk 2
device /dev/hdi3
raid-disk 3
device /dev/hdk3

================
FSTAB

/dev/hda1 /boot reiserfs noauto,notail 1 2
/dev/md0 / reiserfs notail 0 1
/dev/hd2 none swap defaults,pri=1 0 0
/dev/hdc2 none swap defaults,pri=1 0 0
/dev/hdi2 none swap defaults,pri=1 0 0
/dev/hdk2 none swap defaults,pri=1 0 0

etc...............

================

The hardware stuff....

Motherboard Epox 8K7+ w/onboard hpt raid
AMD 2200+ cpu
768Mb DDR ram
4 x 80 Western Digital JB 8Mb cache Hard Drives

there are 2 drives per IDE controller each on Master. I move my Plextor Burner and CD-Rom to a Promise 66 PCI controller card. The only issue with this setup is there are alot of cables in the case. Fortunately for me I had the forsight to buy and Aopen Server tower.

Oh, and my kernel is 2.6.4-rc Love-Sources.

My final statement is I know nothing about this sort of stuff. I just wanted to see if I could do it. Does this arrangement run faster than the old way with one drive for this partition and one drive for that partition? The answer is clear YES.

Does it provide the most performance for my hardware configuration... I don't know. Is this a dangerous arrangement with out Raid 1... PROBABLY. But is was fun and frustrating getting this working and I learnt some new Linux stuff.

cyrillic · Posted: Wed Apr 14, 2004 12:43 am Post subject:

DancesWithWords · Posted: Wed Apr 14, 2004 1:34 am Post subject:

well here is what I got from hdparm

hdparm -tT /dev/md0

Timing buffer-cache reads: 1112 MB in 2.00 seconds = 555.81 MB/sec
Timing buffered disk reads: 166 MB in 3.01 seconds = 55.16 MB/sec

So what do these figures mean?

These are ATA133 drives, but this motherboard only supports ATA100. So for sure this could possess purformance problems. Since I'm in the experimenting mood and I know what to do I'll try them in the master/slave configuration. to see what happens.

Now I notice that the 2.6 support reverse order if you have and extra pci IDE controller, so I will also pick up a Promise ATA133 Fastrak control to see what that adds to performance.

Funny this all started cause I wanted to get faster access time to my Star Catologues that I use with Xephem and Sky Charts.

cyrillic · Posted: Wed Apr 14, 2004 1:50 am Post subject:

DancesWithWords · Posted: Wed Apr 14, 2004 2:08 am Post subject:

figures for the individual drivers:

bash-2.05b# hdparm -tT /dev/hda /dev/hdc /dev/hdi /dev/hdk

/dev/hda:
Timing buffer-cache reads: 1092 MB in 2.01 seconds = 543.91 MB/sec
Timing buffered disk reads: 114 MB in 3.03 seconds = 37.58 MB/sec

/dev/hdc:
Timing buffer-cache reads: 1120 MB in 2.01 seconds = 558.41 MB/sec
Timing buffered disk reads: 104 MB in 3.06 seconds = 34.04 MB/sec

/dev/hdi:
Timing buffer-cache reads: 1112 MB in 2.01 seconds = 554.14 MB/sec
Timing buffered disk reads: 134 MB in 3.03 seconds = 44.25 MB/sec

/dev/hdk:
Timing buffer-cache reads: 1108 MB in 2.00 seconds = 553.25 MB/sec
Timing buffered disk reads: 144 MB in 3.03 seconds = 47.56 MB/sec

cyrillic · Posted: Wed Apr 14, 2004 2:11 am Post subject:

That's interesting ...

I thought for sure /dev/hda and /dev/hdc would be the faster ones.

DancesWithWords · Posted: Wed Apr 14, 2004 2:38 am Post subject:

Uhmm... You do realize that they're two IDE controllers, each running two drivers as Master and that both IDE Controller are ATA100 capable? Should they therefore have the same speed?

cyrillic · Posted: Wed Apr 14, 2004 2:53 am Post subject:

ATA100 is only the burst speed for the interface. I don't know of any drives that are actually that fast.

There are other settings that can affect performance. You can view and change these with hdparm (see "man hdparm" for more info).

DancesWithWords · Posted: Wed Apr 14, 2004 2:59 am Post subject:

/dev/hda:
multcount = 16 (on)
IO_support = 1 (32-bit)
unmaskirq = 1 (on)
using_dma = 1 (on)
keepsettings = 0 (off)
readonly = 0 (off)
readahead = 256 (on)
geometry = 16383/255/63, sectors = 156301488, start = 0

cyrillic · Posted: Wed Apr 14, 2004 3:17 am Post subject:

/dev/hda and /dev/hdc may have different settings than /dev/hdi and /dev/hdk.

The most important one is "using_dma", without that, performance will really suck. You may be able to gain some performance by playing with those settings.

BlinkEye · Posted: Wed Apr 14, 2004 10:52 pm Post subject:

cyrillic · Posted: Thu Apr 15, 2004 6:59 pm Post subject:

BlinkEye · Posted: Thu Apr 15, 2004 8:46 pm Post subject:

hmm, thanks for the reply. i just installed mm-sources linux-2.6.5-mm6. i got the same performance as with gentoo-dev-sources. i'm not sure if i should trust the hdparm result. a

DancesWithWords · Posted: Sat Apr 17, 2004 12:37 am Post subject:

DancesWithWords · Posted: Sat Apr 17, 2004 12:41 am Post subject:

Further along in my experiment.

New configuration:

IDE Controller !
IDE Channel 1

Master
Slave

IDE Controller 2
Master
Slave

Results:

/dev/md0:
Timing buffer-cache reads: 1144 MB in 2.01 seconds = 570.38 MB/sec
Timing buffered disk reads: 192 MB in 3.02 seconds = 63.52 MB/sec
bash-2.05b#

DancesWithWords · Posted: Sat Apr 17, 2004 1:03 am Post subject:

last experiment..... 4 drive one controller.

master
slave
master
slave

bash-2.05b# hdparm -tT /dev/md0

/dev/md0:
Timing buffer-cache reads: 1096 MB in 2.00 seconds = 547.54 MB/sec
Timing buffered disk reads: 148 MB in 3.03 seconds = 48.80 MB/sec
bash-2.05b#