I'm planning a home storage build, and one thing I want to understand before I commit is how to grow a RAID5 array safely. Here's what I've learned.

For demonstration purposes I'm going to do it in VirtualBox. You can say it’s bottlenecked intentionally for demonstration purposes, and it’s at least partially true.

This is how I'm going to reach my starting point from zero:

sudo parted /dev/sdb --script mklabel gpt mkpart primary 1MiB 100% set 1 raid on

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the 1MiB partition alignment matters for RAID performance, make sure your partitions align to mebibyte boundary.

sudo parted /dev/sdc --script mklabel gpt mkpart primary 1MiB 100% set 1 raid on sudo parted /dev/sdd --script mklabel gpt mkpart primary 1MiB 100% set 1 raid on

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I'm doing this on VirtualBox, all the affected virtual hard drives are the same capacity

sudo mdadm --create /dev/md0 --level = 5 --raid-devices = 3 /dev/sdb1 /dev/sdc1 /dev/sdd1 sudo mkfs.ext4…