&gt; md RAID will require a lengthy reshape<p>Array reshapes are rare, and it&#x27;ll only use idle IO bandwidth anyway. Redundancy is guaranteed during the whole process. So I don&#x27;t see this as a problem.<p>&gt; BTRFS supports adding a new drive, reshape (balance) is optional<p>Thanks for pointing this out. I didn&#x27;t know btrfs supported array reshapes. I&#x27;m waiting for it to mature (RAID5&#x2F;6 was only added in 3.19, for example) but I expect I&#x27;ll switch over at some point, probably at the point it&#x27;s considered &quot;boring&quot; (exactly the experience I want from my filesystems).