Due to my increasing amount of important data, I need a software RAID5 array for redundancy, flexibility and cost effectiveness.
ZFS is not an option for me, since my distro (OpenWrt) does not support it. Btrfs RAID5 is broken for so long and it is unlikely the developers can fix it. And from what I've heard, 𝐋𝐕𝐌's RAID5 is nowhere comparable to that of 𝐦𝐝𝐚𝐝𝐦.
Now my idea is classically simple: 𝐫𝐞𝐚𝐥 𝐝𝐞𝐯𝐢𝐜𝐞𝐬 → 𝐦𝐝𝐚𝐝𝐦 → 𝐋𝐔𝐊𝐒 (optional) → 𝐥𝐯𝐦𝟐 → 𝐟𝐢𝐥𝐞𝐬𝐲𝐬𝐭𝐞𝐦 (I'd like to go with Btrfs for block checksum and transparent zstd compression).
What would happen when I add/remove HDDs to grow or shrink my 𝐦𝐝𝐚𝐝𝐦 RAID5 device? Can the 𝐋𝐔𝐊𝐒 and 𝐋𝐕𝐌 devices be grown or shrunk accordingly or it is not possible?