Contacting support is your best bet here.

From: <toasters-bounces@teaparty.net> on behalf of Mike Thompson <mike.thompson@gmail.com>
Date: Tuesday, August 7, 2018 at 12:21 PM
To: "Toasters@teaparty.net" <Toasters@teaparty.net>
Subject: wafl.vol.walloc.rsv.failmount


Looks like we filled up an aggregate that we dump backups into.

Filer bounced itself, to take the aggregate offline, which is an interesting way to deal with the situation:

Aug  6 01:39:46 filer1b [filer1b:wafl.vol.walloc.rsv.offline:error]: Volume backups free space reserve is critically low. Rebooting system to take volume offline. Please contact support for assistance.

Anyway, the aggr is in restricted state now, and when I try to online it, event log says:

8/7/2018 08:43:46   filer1b  WARNING  wafl.vol.walloc.rsv.failmount: Failing mount of volume backups. Free space reserve is too low. Please contact support for assistance.

I'd really like to not have to blow this aggr away and re-run all these backups.  Presumably there's a way to get this back online.

This is on cdot 8.2.4p4

Any ideas?