Date: Wed, 3 Jul 2024 23:48:57 -0400 From: "Kevin P. Neal" <kpn@neutralgood.org> To: William Dudley <wfdudley@gmail.com> Cc: freebsd-questions <freebsd-questions@freebsd.org> Subject: Re: help with full zfs "partitions" - can't delete files Message-ID: <ZoYbqfM06Yk7LF8j@neutralgood.org> In-Reply-To: <CAFsnNZKH0A8FztcB9Ntq3CJK0jF1oAhgH02eJjds56s3-JAmFQ@mail.gmail.com>
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I'm not sure this was ever answered, so I'll chime in with advice for the future. On Mon, Jun 03, 2024 at 04:28:12PM -0400, William Dudley wrote: > The problem: > FreeBSD 13.3 amd64 system, with > a zfs pool built from two physical drives. > The zfs pool has 7 "partitions" (is that what they're called?) They're called "datasets". ZFS can use an entire disk, or it can live in a partition. The whole disk or partition is the container for the pool. Inside the pool are datasets. > I was copying files over from another machine and didn't realize that > I filled one of the partitions. > I can't proceed now with this one full partition. Strictly speaking, the pool is full because of the size of the dataset. The old-school advice for avoiding this is to set the property refreservation=1G on the top dataset of the pool. I had heard that this wasn't necessary anymore. But your report sounds like it actually is still needed. The reason this works is because it reserves 1G of space for that dataset so if the pool is otherwise filled there will still be that 1G free. You aren't supposed to use the top dataset for anything except child datasets. By convention, at least. Since ZFS is a copy-on-write filesystem you need free space to make any changes, but if the pool is totally full you can't make any changes. This leads to the absurd situation where the pool is so full you can't delete anything. BUT, if you have that 1G of reserved space in the top dataset then you'll always have free space and thus can always delete things or whatever. > Every single command fails due to "out of space". (Side note: It doesn't hurt to reserve that 1G of space unless you really, really need that last little scrap of space. But at point fragmentation becomes a very serious issue and you'll have terrible performance issues so, really, don't let it get to that point.) -- Kevin P. Neal http://www.pobox.com/~kpn/ "Good grief, I've just noticed I've typed in a rant. Sorry chaps!" Keir Finlow Bates, circa 1998help
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