Agreed.  I don&#x27;t think anyone is arguing that you shouldn&#x27;t do it.<p>What I believe, and what I think others have also concluded, is that it <i>shouldn&#x27;t be fatal</i>.  That is, when the dust has settled and you trim down usage and have a decent maintenance outage, you should be able to defrag the filesystem and get back to normal.<p>That&#x27;s not possible with ZFS because there is no defrag utility ... and I have had it explained to me in other HN threads (although not convincingly) that it might not be possible to build a proper defrag utility.