From owner-freebsd-stable@FreeBSD.ORG Tue Mar 11 15:28:46 2014 Return-Path: Delivered-To: freebsd-stable@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 197278BF for ; Tue, 11 Mar 2014 15:28:46 +0000 (UTC) Received: from smtp.LaTech.edu (smtp.LaTech.edu [138.47.18.140]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id D0972367 for ; Tue, 11 Mar 2014 15:28:45 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp.LaTech.edu (Postfix) with ESMTP id D4D702A827 for ; Tue, 11 Mar 2014 10:28:33 -0500 (CDT) X-Virus-Scanned: amavisd-new at latech.edu Received: from smtp.LaTech.edu ([127.0.0.1]) by localhost (smtp.latech.edu [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 3JqzjgY0irsc for ; Tue, 11 Mar 2014 10:28:32 -0500 (CDT) Received: from smtp.LaTech.edu (localhost [127.0.0.1]) by smtp.LaTech.edu (Postfix) with ESMTP id 9CE562A81C for ; Tue, 11 Mar 2014 10:28:32 -0500 (CDT) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=latech.edu; h=message-id :date:from:mime-version:to:subject:content-type; s=latech; bh=OD JAzRqpzWZXokOqYmuBk3lFURU=; b=PB4hEMsSp1pGt9r+qRa0RKz2QW49WQOsIr OUwo1fU32HVY4kaxQL/Ep1sEyTaye6Vhfnj7pCK0W4bme/dIgCzGjhbeT1bt3fPQ MBUW7w1jFPpmFQb9QfYmewAxPdsM1vHxlF4BT3KD/4t29dzZxIpFntG8NApQStM1 VzzOTBedM= DomainKey-Signature: a=rsa-sha1; c=nofws; d=latech.edu; h=message-id :date:from:mime-version:to:subject:content-type; q=dns; s=latech; b= tFiDaWBqID7GN/8wU0wtbuiEQPFSJzG3iolKKyKej5c8iFTVKyXrVFfn363gs/SG yqfscDHTfbXjs9Rx6YRC8lUQshwBBJTS6pCVSji52ZlDF0a8m8catQHswBQL6VyK V9IuXa3/keE0luEOQVT0hKP/oTvxvIG3a7aTjveP1s0= Received: from atlantis.latech.edu (atlantis.LaTech.edu [138.47.18.149]) by smtp.LaTech.edu (Postfix) with ESMTPSA id 9987F2A81A for ; Tue, 11 Mar 2014 10:28:32 -0500 (CDT) Message-ID: <531F2BA0.6000105@LaTech.edu> Date: Tue, 11 Mar 2014 10:28:32 -0500 From: Danny Schales User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: freebsd-stable@freebsd.org Subject: ZFS UNMAP performance X-Enigmail-Version: 1.6 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="lemxcvxrNrOE5PIuu3aevs6BM6GheFRhf" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Mar 2014 15:28:46 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --lemxcvxrNrOE5PIuu3aevs6BM6GheFRhf Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable I'm seeing very slow performance with certain operations on a ZFS filesystem built on ISCSI LUN's on a 10.0 system (new ISCSI implementation). The issue appears to be with BIO_DELETE operations. Monitoring the system with gstat shows expected times for read and write operations, but deletes are in the multiple hundreds of milliseconds under normal operation. Destroying a snapshot sends the times to astronomical levels. sysctl says the system is using UNMAP for deletes: kern.cam.da.0.delete_method: UNMAP I searched and found where Oracle issued a performance alert for Solaris 11.1 where ZFS using UNMAP was in use. Here's a link to a blog discussing it: http://schalwad.blogspot.com/2013/12/solaris-111-zfs-write-performance.ht= ml Is FreeBSD also impacted? If so, is there a fix or a workaround? Thanks Danny Schales --lemxcvxrNrOE5PIuu3aevs6BM6GheFRhf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iEYEARECAAYFAlMfK6AACgkQymYKbvs0SzFBkQCfUITyFSlvDqYD69EH1kXCFnj7 PisAni+7hyFoieLQCgO2omXEe1RVqG5/ =is8D -----END PGP SIGNATURE----- --lemxcvxrNrOE5PIuu3aevs6BM6GheFRhf--