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HowTo Single Disk to RAID: differenze tra le versioni
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Final edit, everything should be there
(Again, saving, not complete) |
(Final edit, everything should be there) |
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| Riga 3: | Riga 3: | ||
== Context == | == Context == | ||
We sat up a new/old server, [[BitArno]], it has a nice /home of ~6TB backed by a RAID and a separate | We sat up a new/old server, [[BitArno]], it has a nice /home of ~6TB backed by a RAID and a separate disk for the / partition. As the drive for the / was tested before getting to production resulting in no errors we tought we didn't need a RAID for it. We installed debian stable 8.1, sat up every service, went to bed just to wake up with a hung server refusing to boot. | ||
An on site check was required, we got there and found out that the / drive was failing to reallocate sectors, we fsck'ed it and it booted. "Great!" that same evening it was failing again and so we decided to switch from a single disk root to a RAID1 backed root expecially because we do use commodity hardware taken from old computers. | An on site check was required, we got there and found out that the / drive was failing to reallocate sectors, we fsck'ed it and it booted. "Great!" that same evening it was failing again and so we decided to switch from a single disk root to a RAID1 backed root expecially because we do use commodity hardware taken from old computers. | ||
| Riga 22: | Riga 22: | ||
== Step by step guide == | == Step by step guide == | ||
Here I'll try to cover step by step the command we used, it has been a while since we did it so I'm not 100% sure I'll remember everything | Here I'll try to cover step by step the command we used, it has been a while since we did it so I'm not 100% sure I'll remember everything | ||
First a layout of the partition befor the RAID | First a layout of the partition befor the RAID | ||
sda 8:0 0 114.5G 0 disk | sda 8:0 0 114.5G 0 disk | ||
| Riga 104: | Riga 105: | ||
It was time to install grub and regenerate the image to contain LVM and RAID modules, this was the hardest part as we wrongly supposed all the modules were already present. | It was time to install grub and regenerate the image to contain LVM and RAID modules, this was the hardest part as we wrongly supposed all the modules were already present. | ||
We added "domdadm" to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grub, the line should look something like | |||
cat /etc/default/grub| grep -i cmdli | |||
GRUB_CMDLINE_LINUX_DEFAULT="quiet domdadm" | |||
And we added the modules needed to GRUB_PRELOAD_MODULES in the same file, if the line don't exist create it | |||
GRUB_PRELOAD_MODULES="lvm diskfilter mdraid1x" | |||
Then it was time to install grub on both HDD in the MBR, note that it wasn't needed to specify the boot partition as we were in a chroot | |||
grub-install /dev/sda | |||
grub-install /dev/sde | |||
And just to be sure | |||
update-grub | |||
We exited from the chroot, unmounted everything, rebooted and kept our finger crossed till the password prompt of the root-on-RAID booted system. | |||
This last step I simplified, we made several errors and had to boot into live several times, because we kept forgetting to add the needed modules and command lines arguments | |||
To be sure to boot from the raid root you can edit the grub entry before booting, make sure it's like the following | |||
insmod mdraid1x | |||
Have to be present inside the menuentry section of your os and the linux entry looks similar to | |||
linux /vmlinuz-3.16.0-4-amd64 root=/dev/mapper/ba--system-root ro quiet domdadm | |||
As we failed to achieve everithing on the first try we edited the grub command line and the performed grub install from the booted system. | |||
Once we managed to boot we had to finalize the process and add the old drive to the RAID array | |||
We backed up the partition table of the new disk | |||
sfdisk -d /dev/sde > /tmp/savetablesde | |||
Unmounted the automatically-mounted /dev/sda[1,2,5] deactivating the swap and LVM | |||
swapoff /dev/mapper/bitarno-system-swap | |||
vgchange -an bitarno--system | |||
Whiped out all the old drive first 100M | |||
dd if=/dev/zero of=/dev/sda bs=100M count=1 | |||
sync | |||
And in the end we copied the partition table on the old disk | |||
sfdisk /dev/sda < /tmp/savetablesde | |||
And we added the partitions to the array | |||
mdadm /dev/md1 --add /dev/sda1 | |||
mdadm /dev/md2 --add /dev/sda5 | |||
DONE! | |||
You can check the status of the resync of mdadm with | |||
cat /proc/mdstat | |||
== Issues == | == Issues == | ||