From owner-freebsd-fs@FreeBSD.ORG Wed Sep 3 13:20:55 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D3CEA463 for ; Wed, 3 Sep 2014 13:20:55 +0000 (UTC) Received: from smarthost1.greenhost.nl (smarthost1.greenhost.nl [195.190.28.81]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 963CF1763 for ; Wed, 3 Sep 2014 13:20:55 +0000 (UTC) Received: from smtp.greenhost.nl ([213.108.104.138]) by smarthost1.greenhost.nl with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.72) (envelope-from ) id 1XPAUW-0002F6-DI for freebsd-fs@freebsd.org; Wed, 03 Sep 2014 15:20:52 +0200 Content-Type: text/plain; charset=us-ascii; format=flowed; delsp=yes To: freebsd-fs@freebsd.org Date: Wed, 03 Sep 2014 15:20:51 +0200 Subject: external zfs disk keeps writing MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: "Ronald Klop" Message-ID: User-Agent: Opera Mail/12.16 (FreeBSD) X-Authenticated-As-Hash: 398f5522cb258ce43cb679602f8cfe8b62a256d1 X-Virus-Scanned: by clamav at smarthost1.samage.net X-Spam-Level: / X-Spam-Score: -0.2 X-Spam-Status: No, score=-0.2 required=5.0 tests=ALL_TRUSTED, BAYES_50 autolearn=disabled version=3.3.2 X-Scan-Signature: 0cb660a7d4ce909c6359c48b0bded22a 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 13:20:55 -0000 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. Regards, Ronald.