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tech:linux:build_add_raid [2014/12/05 06:43] |
tech:linux:build_add_raid [2014/12/05 06:43] (current) |
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+ | ====== Building an additional raid ====== | ||
+ | My box already had two hard disks in raid10. Wanted to add two more disks in a second raid. Here is what I did. This was on Ubuntu Trusty. | ||
+ | |||
+ | * Boot with Ubuntu install CD | ||
+ | * Go into recover mode | ||
+ | * Navigate until you hit the partition disk option (had to go forward and backward in the wizard to end up here!) | ||
+ | * Perform the partition as you would on a new system, except only do it for the two new disks and leave the existing untouched | ||
+ | * When asked to specify mount point specify / (root) | ||
+ | * Specifying root is not what I //actually// wanted as this was a supplementary data disk (set) | ||
+ | * The install (even recover mode) would not let me proceed if I did not have a root partition mount | ||
+ | * Confirm the write to partition table | ||
+ | * The system will start installing the OS on the new root partition! Not what we wanted of course. | ||
+ | * Press reset (Ctl-Alt-Del) in the middle of the install to force reboot! | ||
+ | * Boot back into the system (as before) with your regular boot disk | ||
+ | * Run ''fdisk -l'' to check that disks are raid are all in place - should be or something went awry | ||
+ | * Use ''blkid'' to determine the UUID of the new raid disk set | ||
+ | * Update ''/etc/fstab'' with mount point (create the mount-point directory first) | ||
+ | * Issue a ''mount -a'' to mount the disks | ||
+ | * Remove the frivolous install files that the Ubuntu installer started to copy in the new set of disks | ||
+ | * Issue a ''cat /proc/mdstat'' to observe raid sync process | ||
+ | * Issue a ''mdadm --detail --scan'' to get the new (and existing ARRAY) details | ||
+ | * Update ''/etc/mdadm/mdadm.conf'' with the new ARRAY details | ||
+ | * Run ''update-initramfs -u'' to add it to the initramfs image | ||
+ | |||
+ | I used the install CD as the process is standard and you can do it via a //tool// as opposed to commands, that I could not find a good comprehensive set of. It is sort of imperfect in that you have to fool the installer into just creating your raid/partitions and force abort the actual install. However it works and does not have any risk. | ||