From owner-freebsd-fs@FreeBSD.ORG Tue Jul 16 20:50:35 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id AFC9B3BB for ; Tue, 16 Jul 2013 20:50:35 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-qe0-x232.google.com (mail-qe0-x232.google.com [IPv6:2607:f8b0:400d:c02::232]) by mx1.freebsd.org (Postfix) with ESMTP id 7449BEF for ; Tue, 16 Jul 2013 20:50:35 +0000 (UTC) Received: by mail-qe0-f50.google.com with SMTP id f6so687080qej.37 for ; Tue, 16 Jul 2013 13:50:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=hIZPC6bzLhXC1kMfDLu3ymjyasMXmaZw7TeZgn7+9Yk=; b=j47h+yi5b7SZEMrWKfDOt1ng8DxYSByxfBMh+tKT7GkzbftVYcPMZJ2Ni8bRzlfDzg 5wYYrLgEPnmqYyjC+HnfIBSi2DH2lg31VPMHV8VAm24ASXiU4wdhgzW/gxAkll8LaGeX MKH5HYWdryrnJFk1pmRvV21zGKW72tOBLJThO/JsIER88o/jsV/icVU3yAy8wPYoRZ+O KyFH+sAPeQ6PbeOWIHv4Elpc91MB51Ky1GiE7sswLM7Y7+UvxOzdKQN+pNXTJwcjSAU0 OiC9JN4r4oAgpdwhxHDFLry/9H9hhFkWu9sbJeNELG+vRWP1QGOS/oPEPTvW/g6eTZzW lkWA== MIME-Version: 1.0 X-Received: by 10.224.79.14 with SMTP id n14mr5545663qak.114.1374007834974; Tue, 16 Jul 2013 13:50:34 -0700 (PDT) Received: by 10.49.49.135 with HTTP; Tue, 16 Jul 2013 13:50:34 -0700 (PDT) In-Reply-To: References: Date: Tue, 16 Jul 2013 13:50:34 -0700 Message-ID: Subject: Re: ZFS memory exhaustion? From: Freddie Cash To: javocado Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: FreeBSD Filesystems X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 16 Jul 2013 20:50:35 -0000 On Tue, Jul 16, 2013 at 1:26 PM, javocado wrote: > I have a couple questions: > > - what does it look like when zfs needs more physical memory / is running > out of memory for its operations? > Disk I/O drops to 0, reading/writing any file from the pool appears to "hang" the console, programs already loaded into RAM continue to work so long as they don't touch the pool, etc. > > - what diagnostic numbers (vmstat, etc.) should I watch for that? > > Top output will show Wired at/near 100% of RAM. > swapinfo shows zero (basically zero) swap usage, so it doesn't look like > things get that bad. > > ZFS uses non-swappable kernel memory, so you won't ever see swap used when ZFS runs out of RAM. Those are the symptoms we've noticed when our ZFS systems have run out of RAM. -- Freddie Cash fjwcash@gmail.com