From owner-freebsd-fs@FreeBSD.ORG Wed Sep 3 13:57:14 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id AC2AA843 for ; Wed, 3 Sep 2014 13:57:14 +0000 (UTC) Received: from mail-ie0-x236.google.com (mail-ie0-x236.google.com [IPv6:2607:f8b0:4001:c03::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7CFE21C50 for ; Wed, 3 Sep 2014 13:57:14 +0000 (UTC) Received: by mail-ie0-f182.google.com with SMTP id rd18so9720414iec.27 for ; Wed, 03 Sep 2014 06:57:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=iNXFS6jQKyiE881O8LlEIDhlzQZn9rr4mqbxP2I2vfY=; b=x0i8+kP/raoCFPDdSTgFTqKnl/BlZYFW3tE87uIQO8t0YXSlzmkute9HeLA+tJIoNa mMdDSXMssIfD5MKj/dOWmD/UP1E8J3nMxnqqig/EZXfTe+gNGx/6cGgecEBOGFH+Eupc o0ST17IMG3hWLwFTLScTAHh/i8ERNRzGqpgkRg64OBc19BAwAeDcy1aSJZ5oluk9TMPC pYHJtsoBtiMeV88XERxzMKOWCIpFF0q0QrBdAJRT7Nju79qkHKPJyXtuK/jZ+JMywBqb Cb6Zknda1UBoowhpoQEXNOtV/a6mNLMKw55ZtfRKagtV83ViwYyRTWm8AqrDqia4mm1w jLig== MIME-Version: 1.0 X-Received: by 10.50.20.225 with SMTP id q1mr37782099ige.36.1409752633470; Wed, 03 Sep 2014 06:57:13 -0700 (PDT) Received: by 10.107.1.19 with HTTP; Wed, 3 Sep 2014 06:57:13 -0700 (PDT) In-Reply-To: References: Date: Wed, 3 Sep 2014 14:57:13 +0100 Message-ID: Subject: Re: external zfs disk keeps writing From: Tom Evans To: Ronald Klop Content-Type: text/plain; charset=UTF-8 Cc: FreeBSD FS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 03 Sep 2014 13:57:14 -0000 On Wed, Sep 3, 2014 at 2:20 PM, Ronald Klop wrote: > Hello, > > I have a disk with ZFS which always writes something every > 'vfs.zfs.txg.timeout' seconds. By default that is 5 seconds. If I make it 30 > I see writing in gstat every 30 seconds. > I only do a backup by zfs send | zfs recv hourly on this disk. So I don't > understand why it still writes something every 5 seconds while I am not > doing anything to this disk. > > How can I debug what is being written every 5 seconds? > > > Some info: > > I am running FreeBSD 10-STABLE. The disk is an external disk connected by > USB. > > ugen3.2: at usbus3 > umass0: on usbus3 > umass0: SCSI over Bulk-Only; quirks = 0x4100 > umass0:4:0:-1: Attached to scbus4 > da0 at umass-sim0 bus 0 scbus4 target 0 lun 0 > da0: Fixed Direct Access SCSI-0 device > da0: 40.000MB/s transfers > da0: 305245MB (625142448 512 byte sectors: 255H 63S/T 38913C) > da0: quirks=0x2 > > Occasionally I have a message like this, but it does not seem to hurt > anything, so it is probably unrelated. > > # bzgrep da0 /var/log/messages* > /var/log/messages.0.bz2:Sep 2 16:49:45 sjakie kernel: > (da0:umass-sim0:0:0:0): WRITE(10). CDB: 2a 00 00 00 03 66 00 00 02 00 > /var/log/messages.0.bz2:Sep 2 16:49:45 sjakie kernel: > (da0:umass-sim0:0:0:0): CAM status: CCB request completed with an error > /var/log/messages.0.bz2:Sep 2 16:49:45 sjakie kernel: > (da0:umass-sim0:0:0:0): Retrying command > > # zpool status extern > pool: extern > state: ONLINE > scan: scrub repaired 454K in 4h36m with 0 errors on Sat Aug 9 08:53:27 > 2014 > config: > > NAME STATE READ WRITE CKSUM > extern ONLINE 0 0 0 > da0 ONLINE 0 0 0 > > errors: No known data errors > > I just created a zpool on da0 so there is no partition table. > zfs set atime=off extern? Cheers Tom