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Providing this answer in the proper format rather than just a link from a comment. "This can happen after an unclean shutdown (like a power fail). Usually removing and re-adding the problem devices will correct the situation." Refer to your specific drive configuration and mdadm version specific documentation for how to do this. Another alternative is ...


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Looking for love in all the wrong places .... Thank you psusi and ppetraki for your helpful replies. You each gave me additional insights into how RAID functions under Linux. It turns out that there was nothing wrong with the disks or the mdadm commands that I was using to create and manipulate the RAID arrays. Once I discovered the ata8 kernel messages, ...


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Make sure you have package 'hfsprogsinstalled:sudo apt-get install hfsprogs`. See How to read and write HFS+ journaled external HDD in Ubuntu without access to OS X?


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There's not much to this. You simply wait until your array is fully synced Shutdown, remove whatever pair you want and stuff that in the new system Boot both systems, each will have a degraded RAID1 with the same uuid Add a slave and resync Done You'll want to change the array UUID on the new system and update the mdadm.conf to auto assemble. There's ...


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You can safely write to any degraded RAID array and not lose any data, that's a standard RAID feature If a disk fails during sync, well it matters which disk that failed. If it was the resync target, who cares, it'll just resync from the master again. If it was the master then the RAID 1 has failed however that member still has the most up to date copy of ...


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If one of the disk fails then it will ruin your whole RAID setup, if the disk were to fail, then you will have to setup your whole RAID over again, so on that note, if at all possible, do not attempt to write file to the disk while in sync.


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I had this problem before. What I did to avoid this error is to edit the grub config. Please try to modify as "nodmraid domdadm" after the "ro" description, and see if it works.


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I had faced this predicament once. I took the gamble and formatted my boot drive. Later on i realized that mdadm can assemble the RAID arrays even after a clean installation. What this means is, you dont need to re-configure the RAID once again. mdadm does it and the RAID device would be active for the system. Run sudo fdisk -l. This will list the RAID ...


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See http://wiki.gentoo.org/wiki/Device-mapper#RAID1 Though I don't think you can boot off it and the management tools are pretty low level. If you can't manage it well then RAID just becomes a great way to lose your data :) It's nowhere near as convenient as using MD to create a RAID and then adding that MD block device as physical volume to a LVM volume ...


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Since you didn't mention creating a filesystem on the raid array and mounting it after creating the array, and mdadm warned you that /dev/sdc1 already has an ext2 filesystem in it, I'm guessing you mean you already have a filesystem in /dev/sdc1, and that is what is being remounted read only. This is because creating a raid array out of a disk or partition ...


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The biggest problem I see is this mdadm: /dev/sdd1 appears to contain an ext2fs file system Also, those partitions should be marked as RAID members (type fd), not Linux filesystems. Which means there are superblocks that extfs tools can latch onto, like fsck, and mess up your world bad. I would strongly recommend that you completely wipe the drives before ...


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I know I'm being a Johnny-come-lately to this question but I'd like to see if I can shed some light on this for anyone searching. First, @ppetraki's answer is excellent. The short answer to "Can I RAID SSDs and boot from them" is "Yes!". Here are instructions for 14.04. Instructions for RAID configuration on 12.04.x are identical, but this tutorial using ...


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You might need to just do an --add and not a --re-add. if you read the man page about --re-add it talks about re-adding the device if the event count is close to the rest of the devices. you can use --examine to find this out. $ mdadm --examine /dev/sd[a-z]1 | egrep 'Event|/dev/sd' mdadm: No md superblock detected on /dev/sda1. /dev/sdb1: Events : ...


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Or just execute the following command: $ sudo dmsetup ls --tree which will show how your block devices are stacked.


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I think the reason for the 4TB volume only being recognized as less than 4 TB is because storage is sold on base 10 and measured in base 2 and formating takes some space. A base 2 terabyte is 1024 gigabytes, a gigabyte is 1024 megabytes and so fourth. Storage is sold in base 10 teragytes, 1TB=1000GB, 1GB=1000MB, and so fourth.so a 4TB drive is 4 X 10^12 and ...


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That's the point of HARDWARE RAID, the physical disks are abstracted away behind the virtual disk you created so all the OS has to care about is one disk. It has no idea it's a RAID volume, it's not necessary.



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