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mdadm configuration


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Hi all.


Turns out that mdadm is supposed to run my motherboard bios raid.


It's detected during the live cd/dvd, but upon install is broken. I have no idea how to activate it.


The intel bios chip is detected correctly:


[root@localhost user]# mdadm --detail-platform
      Platform : Intel(R) Matrix Storage Manager
       Version :
   RAID Levels : raid0 raid1 raid10 raid5
   Chunk Sizes : 4k 8k 16k 32k 64k 128k
   2TB volumes : supported
     2TB disks : not supported
     Max Disks : 6
   Max Volumes : 2 per array, 4 per controller
I/O Controller : /sys/devices/pci0000:00/0000:00:1f.2 (SATA)


and it arrays are detected correctly:


[root@localhost user]# cat /proc/mdstat
Personalities : [raid1] 
md124 : active (auto-read-only) raid1 sdc[1] sdd[0]
     488383488 blocks super external:/md126/0 [2/2] [uU]

md125 : active (auto-read-only) raid1 sdb[1] sda[0]
     625129472 blocks super external:/md127/0 [2/2] [uU]

md126 : inactive sdc[1](S) sdd[0](S)
     5928 blocks super external:imsm

md127 : inactive sda[1](S) sdb[0](S)
     4520 blocks super external:imsm

unused devices: <none>


I can't mount them, they don't appear in hard disk manager as arrays, but individual disks.


Some how I just need to activate them properly and then mount them.


Any help always appreciated.

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Some more info:


[root@localhost user]# mdadm --detail -scan
ARRAY /dev/md/imsm0 metadata=imsm UUID=503346f0:5de6fa79:b9e60bff:92c63eb6
ARRAY /dev/md/imsm1 metadata=imsm UUID=1949119d:b6b492d9:e28677a4:8bd53437
ARRAY /dev/md/Cleggett08_0 container=/dev/md/imsm0 member=0 UUID=899a4b41:e26cfc0a:a4c94658:81ed172d
ARRAY /dev/md/Cleggett13_0 container=/dev/md/imsm1 member=0 UUID=4d99dbc5:d794a739:d4d0d715:45954787


Am I right in thinking that the containers for the arrays are made, but no disks are allocated?


[root@localhost user]# ls -la /dev | grep md
drwxr-xr-x   2 root root         160 Jun  9 22:37 md/
brw-rw----   1 root disk      9, 124 Jun  9 22:37 md124
brw-rw----   1 root disk    259,   1 Jun  9 22:37 md124p1
brw-rw----   1 root disk      9, 125 Jun  9 22:37 md125
brw-rw----   1 root disk    259,   0 Jun  9 22:37 md125p1
brw-rw----   1 root disk      9, 126 Jun  9 22:37 md126
brw-rw----   1 root disk      9, 127 Jun  9 22:37 md127


is assume md/ is root. md124 is the array itself and md124p1 is partition 1 of md124 etc?

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Some info here on activating the array:




the last paragraph mention susing the madadm --examine --scan command and then putting this in your mdadm.conf file. Then ensuring that /etc/fstab matches in terms of the arrays.

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Hi Ian, just seen your post. Let me check that out. For me mdadm is definately broken atm. Data I copy to the array isn't there after reboot, the md numbers act erratically. I'll keep working on it on a secondary install, but will use dmraid for my stable os, as it works :)


More info:


Using blkid I get:


/dev/md124p1: UUID="31632D4D784933D3" TYPE="ntfs" 
/dev/md125: PTTYPE="dos" 
/dev/md124: PTTYPE="dos" 


So I add a line to fstab:


UUID=31632D4D784933D3 /mnt/Videos ntfs-3g defaults,nofail,umask=000 0 0


Now according to df I have:


/dev/md124p1    466G  101M  466G   1% /mnt/Videos


And mount:


/dev/md124p1 on /mnt/Videos type fuseblk (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096)


So it appears that partition 1 is indeed mounted. I can access it though dolphin on /mnt/Videos.


What concerns me is that diskdrake still only sees individual disks with no raid array shown.

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Ok so


[root@localhost user]# mdadm --examine --scan
ARRAY metadata=imsm UUID=1949119d:b6b492d9:e28677a4:8bd53437
ARRAY /dev/md/user13 container=1949119d:b6b492d9:e28677a4:8bd53437 member=0 UUID=4d99dbc5:d794a739:d4d0d715:45954787


Now, I'm further confused, as what part of that do I put in mdadm.conf? Given that with the intel board raids, a container is created, and the arrays created in that? I guess, I should put the lot in really?

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From what I know yes, you copy it all and put it in. That's what I understood from the post. Make sure there are no other ARRAY lines in the /etc/mdadm/mdadm.conf or /etc/mdadm.conf - it depends where this file exists on your system.


No idea where you configured the arrays, whether you did it within the controller, or within Linux. I understood that previously you had it under Linux, and not configured on the Intel controller before booting the system.

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Thanks Ian. The array is constructed in the bios before boot. So the controller handles the array. My /etc/mdadm.conf is generic file that is completely commented out. It'll be a few days before I have time to have a play with it again.

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OK, based on the mdadm command that I gave you before, just put all this in the mdadm.conf, then make sure mdadm is enabled at bootup:


chkconfig mdadm on


and then reboot, and see what happens. Check that it's active with:


cat /proc/mdstat

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  • 11 months later...

Well, I've messed around with mdadm on both Mga3 and Mga4, and have bits of luck here and there, but no solid solution. I've spent many hour scouring forums and conversing via IRC.


In the end to have a usable system, I've edited /lib/systemd/fedora-storage-init so that dmraid handles my raid arrays, and completely commented out mdadm. While in Mga3, this left me with a system that wouldn't shutdown fully, requiring a long press on the on/off button, this setup works perfectly with Mga4.


I would prefer that I could have got mdadm to work, but it just never came together completely. When Mga5 comes around I'll have another go at seeing if mdadm will work, but it's also possible by then that my 6/7 year old system maybe updated to something with some real grunt.


Thanks for your time Ian.

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