From owner-freebsd-fs@FreeBSD.ORG Tue Mar 19 20:45:42 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 A103FCD8 for ; Tue, 19 Mar 2013 20:45:42 +0000 (UTC) (envelope-from zbeeble@gmail.com) Received: from mail-vc0-f173.google.com (mail-vc0-f173.google.com [209.85.220.173]) by mx1.freebsd.org (Postfix) with ESMTP id 59094662 for ; Tue, 19 Mar 2013 20:45:42 +0000 (UTC) Received: by mail-vc0-f173.google.com with SMTP id gd11so774926vcb.18 for ; Tue, 19 Mar 2013 13:45:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:date:message-id:subject:from:to :content-type; bh=Jd2vuCNMXPekFiWoAhcCnrqbsagPz7kdBqDucUPeamg=; b=QbbE9+3zdH4cc8wsavLi5Iu0NYYSDvH7F9ydvQdifZOToDhz8x672/aQ8aMe8paTA5 aapxAwPooo8orX3eZAjv3LTZQG9C2XrD3jOGqZLPSL99ZVCnrAnCoq55qq+aceiFk32K Jxq9dx8QXtzvZn03+osscpiqXlou2SYrjQOIeDeIjL+bu8Xr9ZRCC5n8MhbFEqIZh2+f GXkVuUsDgOvAKjP/9sMRd+6H0V8kbmBXocgvr4Y92AknKZNztf414VthV5YcVQtLIh/+ EhZa4YFOh90hQIB5WNg8W2rjz4ISGgomnCL9SWDpQTy73L1Jb6Y4AIEKepUzlil7DpvJ AxPQ== MIME-Version: 1.0 X-Received: by 10.220.222.8 with SMTP id ie8mr4674577vcb.27.1363725936614; Tue, 19 Mar 2013 13:45:36 -0700 (PDT) Received: by 10.220.232.6 with HTTP; Tue, 19 Mar 2013 13:45:36 -0700 (PDT) Date: Tue, 19 Mar 2013 16:45:36 -0400 Message-ID: Subject: ZFS: Almost a minute of dirty buffers? From: Zaphod Beeblebrox To: freebsd-fs Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 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, 19 Mar 2013 20:45:42 -0000 During a recent protracted power outage at home, it came time to shutdown my ZFS fileserver. This doesn't happen often --- it's a reliable performer. The kicker is that _after_ the buffers have been sync'd for UFS (root/var/usr on UFS), ZFS spends some time shutting down --- or that's what I believe since the disk usage lights on the ZFS drives are going crazy. ... and ZFS takes nearly a minute of very active disk to shutdown ?!!? Are these dirty buffers? What is it doing? This period of disk blinking seems to be related to uptime (ie: longer uptime, longer blinking on shutdown). For the curious, my ZFS config is: [1:1:301]root@virtual:~> zpool status pool: vr2 state: ONLINE scan: resilvered 30.8M in 0h2m with 0 errors on Tue Feb 26 20:41:45 2013 config: NAME STATE READ WRITE CKSUM vr2 ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 label/vr2-d0 ONLINE 0 0 0 label/vr2-d1 ONLINE 0 0 0 label/vr2-d2a ONLINE 0 0 0 label/vr2-d3a ONLINE 0 0 0 label/vr2-d4 ONLINE 0 0 0 label/vr2-d5 ONLINE 0 0 0 label/vr2-d6 ONLINE 0 0 0 label/vr2-d7c ONLINE 0 0 0 label/vr2-d8 ONLINE 0 0 0 raidz1-1 ONLINE 0 0 0 gpt/vr2-e0 ONLINE 0 0 0 gpt/vr2-e1 ONLINE 0 0 0 gpt/vr2-e2 ONLINE 0 0 0 gpt/vr2-e3 ONLINE 0 0 0 gpt/vr2-e4 ONLINE 0 0 0 gpt/vr2-e5 ONLINE 0 0 0 gpt/vr2-e6 ONLINE 0 0 0 gpt/vr2-e7 ONLINE 0 0 0 errors: No known data errors I know that the two vdevs are not the same size (9 disks and 8 disks), but I noticed this behavior when there was only one vdev in this array, too. Most of the ZFS usage is via NFS, SMB or iSCSI.