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Old 11-29-2005, 09:49 PM   #1
ggduff
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RAID5 using mdadm, how to mount /dev/md0?


After using mdadm to configure 3 identical IDE drives in a RAID5 array as /dev/md0, how do I now 'mount' this array and start using it? The mdadm tutorial that I used to make the array stopped short of telling me how to do that.

The OS is Ubuntu 5.10, on hda1 (80GB Maxtor with default partitions.) This is the master drive on the primary IDE controller.

The RAID5 drives are all 300GB Maxtors (3), each with a single primary ext3 partition as: /dev/hdb1, /dev/hdc1, and /dev/hdd1

I partitioned them first, then formatted them with their filesystems, and then created the RAID using the tutorial listed here: http://www.linuxdevcenter.com/lpt/a/2776

I did not use the optional mdadm.conf file.

I go into Disk Administrator and the 'enable' option does not mount the drive, nor can I mount it manually. Also, in the Disk Administrator I notice that the first two drives do not say ext3 filesystems, but rather unknown and the third disk in the array now says unformatted. All 3 said ext3 before setting up the RAID. I'm assuming this is normal, as I know RAID5 needs that 3rd disk for parity.

Thanks for any suggestions!
 
Old 11-30-2005, 03:05 PM   #2
acid_kewpie
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you just mount it like any other block device, with the mount command. once it's formatted there is no difference whatsoever between mounting /dev/md0 or /dev/hda2 etc...
 
Old 11-30-2005, 04:41 PM   #3
WhatsHisName
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Re: RAID5 using mdadm, how to mount /dev/md0?

Quote:
Originally posted by ggduff
...The RAID5 drives are all 300GB Maxtors (3), each with a single primary ext3 partition as: /dev/hdb1, /dev/hdc1, and /dev/hdd1

I partitioned them first, then formatted them with their filesystems, and then created the RAID ...
You need to format the raid device after you create it, not before. Thatís probably why you cannot mount it, because it doesnít have a filesystem.

For example:

# mdadm -C /dev/md0 -l5 -n3 /dev/hd[bcd]1
# mke2fs -j /dev/md0

As far as the partition-type labels, they really should be changed to type ďfdĒ (linux raid auto). Otherwise, you will probably start getting some odd error messages during boot.

Also, are you really using 2 slave drives in the raid5? Thatís a really bad idea. You should buy 1 or 2 PCI IDE controller cards and mount the drives as one drive per IDE channel.

Last edited by WhatsHisName; 11-30-2005 at 04:46 PM.
 
Old 11-13-2007, 06:18 PM   #4
ufmale
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md0 is gone after reboot

i use mdadm --create md0 option raid0, for my sdb1 and sdc1
then format the md0 and mount to /mnt/myraid

For some reason, after booting the machine, my md0 is gone.
Although i still see the drive by calling $ fdisk -l

I am using the loadable raid card driver module that get called in the rc.sysinit. I did not add the driver to the kernel yet since I don't know how to do it at the moment.

Does anyone know how to avoid formating md0 and remounting everytime I boot the machine?
 
Old 11-14-2007, 01:59 AM   #5
acid_kewpie
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please don't drag up dead threads. if you have a new question, start a new thread.
 
  


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