Ubuntu – How to automount a fake raid

dmraidraid

Hardware

Asus K8N4-E Deluxe Mobo
Sil 3114 fake raid, onboard
2 Seagate 250 gb hd, hosting my /home
A backup on a separate hard disk of /home

What I have so far

I've made the raid using the Sil 3114 firmware. I'm using raid level 1. I have a bash script I run as root as soon as I get a prompt:

dmraid -ay
mount /dev/mapper/sil*1 /home

The problem

I have to logon as root and use that stupid bash script every boot. Ubuntu isn't automatically understanding the raid volume. I haven't put the raid volume in fstab because it doesn't exist on boot. How do I have /home from my fakeraid automounted at boot?

Best Answer

Here are the steps needed to setup fakeraid and get relevant partitions auto-mounted:

Install the dmraid package:
```
sudo apt-get install dmraid
```
Reboot (this is because dmraid adds itself into initramfs)

The fakeraid device should appear e.g.:

$ ls /dev/mapper/*
brw-rw---- 1 root disk 252,   0 Dec  6 16:21 /dev/mapper/isw_dhdhchcbaf_Dima
brw------- 1 root root 252,   1 Dec  6 16:21 /dev/mapper/isw_dhdhchcbaf_Dima1
crw------- 1 root root  10, 236 Dec  6 16:22 /dev/mapper/control

Above, *Dima is the fakeraid device, while *Dima1 is the partition. If you don't have *N, you need to create a partition table, create a partition, format ot with a filesystem and reboot again.

In Ubuntu, all partitions are mounted by UUID by default. Let's find out UUID:

$ sudo blkid
[sudo] password for xnox: 
/dev/sda: TYPE="isw_raid_member" 
/dev/sdb: TYPE="isw_raid_member" 
/dev/mapper/isw_dhdhchcbaf_Dima1: UUID="92edd1fd-94c5-4617-b829-fa4a8378b7ae" TYPE="ext4" 
/dev/sdc1: UUID="A904-D2E7" TYPE="vfat" 
/dev/sdc2: UUID="6669d411-80c3-41cc-a629-ad84e1ee6854" TYPE="ext4" 
/dev/sdc3: UUID="2bf263f1-753f-4b2e-92a6-b00381515e0c" TYPE="swap" 
/dev/sdd1: UUID="C499-1A68" TYPE="vfat"

See that the wanted one is UUID="92edd1fd-94c5-4617-b829-fa4a8378b7ae"

Therefore the /etc/fstab entry would be:

UUID="92edd1fd-94c5-4617-b829-fa4a8378b7ae" /srv/dima ext4 defaults 0 0

Related Solutions

Ubuntu – How to access a fake raid

Fake raid is accessed with the dmraid utility, not mdadm. It should also work out of the box with recent Ubuntu releases. See http://wiki.ubuntu.com/FakeRaidHowto for more information, though much of the how to part does not apply with recent releases, since as I said, it now just works automatically.

Ubuntu – Installing Ubuntu with Fake RAID 1

So, run installation of Ubuntu 12.04.1 x64 LTS using alternate CD.

During the installation I selected manual partitioning and to:
- Use and Format / (root)
- Use and Format SWAP
- Use and Keep data on /home
- Use and Keep data on /data

After I clicked "Continue" I get error creating and formatting SWAP partition.

I go to terminal with Alt + F2 (?) and hit enter.
I discovered that there was visible RAID as only disk with NO partitions.
Something like this:

arek@domek:/var/log/installer$ ls -l /dev/mapper/
lrwxrwxrwx 1 root root 7 Oct  7 20:17 /dev/mapper/pdc_jhjbcaha -> ../dm-0

arek@domek:/var/log/installer$ ls -l /dev/dm*
brw-rw---- 1 root disk 252, 0 Oct  7 20:17 /dev/dm-0

So I switched to log console Alt+F3 (?) and saw errors like below:

Oct  7 14:02:45 check-missing-firmware: /dev/.udev/firmware-missing does not exist, skipping
Oct  7 14:02:45 check-missing-firmware: /run/udev/firmware-missing does not exist, skipping
Oct  7 14:02:45 check-missing-firmware: no missing firmware in /dev/.udev/firmware-missing /run/udev/firmware-missing
Oct  7 14:02:45 anna-install: Installing dmraid-udeb
Oct  7 14:02:45 anna[12599]: DEBUG: retrieving dmraid-udeb 1.0.0.rc16-4.1ubuntu8
Oct  7 14:02:49 anna[12599]: DEBUG: retrieving libdmraid1.0.0.rc16-udeb 1.0.0.rc16-4.1ubuntu8
Oct  7 14:02:49 anna[12599]: DEBUG: retrieving kpartx-udeb 0.4.9-3ubuntu5
Oct  7 14:02:49 disk-detect: Serial ATA RAID disk(s) detected.
Oct  7 14:02:55 disk-detect: Enabling dmraid support.
Oct  7 14:02:55 disk-detect: RAID set "pdc_jhjbcaha" was activated
Oct  7 14:02:55 HERE --> dmraid-activate: ERROR: Cannot retrieve RAID set information for pdc_jhjbcaha 
Oct  7 14:02:56 check-missing-firmware: /dev/.udev/firmware-missing does not exist, skipping
Oct  7 14:02:56 check-missing-firmware: /run/udev/firmware-missing does not exist, skipping
Oct  7 14:02:56 check-missing-firmware: no missing firmware in /dev/.udev/firmware-missing /run/udev/firmware-missing
Oct  7 14:02:57 main-menu[428]: DEBUG: resolver (libnewt0.52): package doesn't exist (ignored)
Oct  7 14:02:57 main-menu[428]: DEBUG: resolver (ext2-modules): package doesn't exist (ignored)
Oct  7 14:02:57 main-menu[428]: INFO: Menu item 'partman-base' selected
Oct  7 14:02:57 kernel: [  316.512999] NTFS driver 2.1.30 [Flags: R/O MODULE].
Oct  7 14:02:57 kernel: [  316.523221] Btrfs loaded
Oct  7 14:02:57 kernel: [  316.534781] JFS: nTxBlock = 8192, nTxLock = 65536
Oct  7 14:02:57 kernel: [  316.554749] SGI XFS with ACLs, security attributes, realtime, large block/inode numbers, no debug enabled
Oct  7 14:02:57 kernel: [  316.555336] SGI XFS Quota Management subsystem
Oct  7 14:02:58 md-devices: mdadm: No arrays found in config file or automatically
Oct  7 14:02:58 partman:   No matching physical volumes found
Oct  7 14:02:58 partman:   No volume groups found
Oct  7 14:02:58 partman:   Reading all physical volumes.  This may take a while...
Oct  7 14:02:58 partman-lvm:   No volume groups found
Oct  7 14:02:58 partman: Error running 'tune2fs -l /dev/mapper/pdc_jhjbcaha'
Oct  7 14:02:58 partman: Error running 'tune2fs -l /dev/mapper/pdc_jhjbcaha'
Oct  7 14:02:58 partman: Error running 'tune2fs -l /dev/mapper/pdc_jhjbcaha'
Oct  7 14:06:11 HERE --> partman: mkswap: can't open '/dev/mapper/pdc_jhjbcaha2': No such file or directory
Oct  7 14:07:28 init: starting pid 401, tty '/dev/tty2': '-/bin/sh'
Oct  7 14:15:00 net/hw-detect.hotplug: Detected hotpluggable network interface eth0
Oct  7 14:15:00 net/hw-detect.hotplug: Detected hotpluggable network interface lo

As You can see there are 2 errors

Oct  7 14:02:55 dmraid-activate: ERROR: Cannot retrieve RAID set information for pdc_jhjbcaha

and

Oct  7 14:06:11 partman: mkswap: can't open '/dev/mapper/pdc_jhjbcaha2': No such file or directory

I looked in the internet and try to run command "dmraid -ay" and get something like that:

dmraid -ay
/dev/mapper/pdc_jhjbcaha -> Already activated
/dev/mapper/pdc_jhjbcaha1 -> Successfully activated
/dev/mapper/pdc_jhjbcaha2 -> Successfully activated
/dev/mapper/pdc_jhjbcaha3 -> Successfully activated
/dev/mapper/pdc_jhjbcaha4 -> Successfully activated
/dev/mapper/pdc_jhjbcaha5 -> Successfully activated
/dev/mapper/pdc_jhjbcaha6 -> Successfully activated

Then I returned to installer with Alt+F1 (?) and click "Return" to return to partitioning menu. I did NOT change anything just selected again "Continue" and everything goes smoothly.

I hope this will help someone.

arkadius