mdadm mdadm: cannot open /dev/sda1: Device or resource busy
Solution 1
do I need to
...
create the arrays for / and /boot while they are not mounted?
Precisely.
I hope you also realised that the old contents will be wiped in the process, so you might want to create a new array with one device missing (use mdadm --level=10 --raid-devices=8 --missing /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdg1 /dev/sdh1
). Then format the filesystem on the new array volume and copy all data from /dev/sda1 to it. Then reboot from the array (thus NOT using the /dev/sda1 root) and actually add /dev/sda1.
Do not forget to adjust the bootloader accordingly.
Solution 2
Just try to stop before reassambling array :
sudo mdadm -Esv
sudo mdadm --stop /dev/md*
sudo mdadm --misc --scan --detail /dev/md0
sudo mdadm -v --assemble "$array" "$disk1$part" "$disk2$part"
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Backtogeek
Updated on September 18, 2022Comments
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Backtogeek almost 2 years
I am having trouble going from a single disk to raid 10
The command issued is:
mdadm --create /dev/md0 --level=10 --raid-devices=8 /dev/sd[abcdefgh]1
The output is:
mdadm mdadm: cannot open /dev/sda1: Device or resource busy
I have verified this has nothing to do with DM:
]# dmsetup status No devices found
The file system is GPT, I used
sgdisk --backup=table /dev/sda
followed bysgdisk --load-backup=table /dev/sdb
through to sdh to copy the partitions tableThe table looks like:
Number Start End Size File system Name Flags 1 1049kB 525MB 524MB ext3 boot 2 525MB 86.4GB 85.9GB ext4 3 86.4GB 90.7GB 4295MB linux-swap(v1) 4 90.7GB 1000GB 909GB
I have created the other arrays fine however I cannot create the raid for the 1st and 2nd partition.
current status:
]# cat /proc/mdstat Personalities : [raid10] md3 : active raid10 sdh3[7] sdg3[6] sdf3[5] sde3[4] sdd3[3] sdc3[2] sdb3[1] sda3[0] 16766976 blocks super 1.2 512K chunks 2 near-copies [8/8] [UUUUUUUU] resync=DELAYED md4 : active raid10 sdh4[7] sdg4[6] sdf4[5] sde4[4] sdd4[3] sdc4[2] sdb4[1] sda4[0] 3552147456 blocks super 1.2 512K chunks 2 near-copies [8/8] [UUUUUUUU] [========>............] resync = 42.5% (1513033344/3552147456) finish=76.2min speed=445722K/sec unused devices: <none>
Can anyone offer any advice, do I need to boot in to a rescue disk and create the arrays for / and /boot while they are not mounted?
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FooBee about 11 yearsYou are likely trying this in a running system while
/dev/sda1
is mounted. Naturally, this can't work, also things are a lot more complicated than just to convert the partitions into a RAID (you need to update the initramfs, the boot loader and/etc/fstab
). If you don't understand this, you shouldn't continue before reading up on this matter.
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Backtogeek about 11 yearsAh ok thanks, usually I would not be doing it this way at all, the server was taken on with 8 drives with the OS on 1 disk only and the others untouched, it might be worth just setting it up again from scratch with the KVMoIP I suppose. I thought it may have been an option to simply dd sda1 and sda2 over to sd[bcdefgh]1 and sd[bcdefgh]2 then create the arrays even with sda1 and sda 2 mounted, I suppose I could still try that with sda1,2 missing then add them to the arrays in resuce mode unmounted but if that is going to wipe everything I might as well just reinstall.
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Hennes about 11 yearsUbuntu is not CentOS, but it is close enough that several of the answers on A.U. also apply. Exaples: askubuntu.com/questions/252795/convert-running-system-to-raid-5 (In your case it is RAID 10 and not RAID5, but the idea is the same: Create the new array and format it, copy data, fix bootloader to boot from the RAID, test, add old partition to the RAID (thus loosing the old content on it).
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Backtogeek about 11 yearsThere was enough information in that link to give me the answers and order of things I needed all sorted now and booting+running on raid 10 Thanks.
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pdem about 3 yearsSorry, but a single link to youtube is a little bit Lazy to get points. The answer was in the video though (for my case) : use
dmsetup
: dmsetup table to get the list, dmsetup remove diskname to remove what's using the drive.