From owner-freebsd-stable@FreeBSD.ORG Sun Jan 4 12:40:30 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DB48E106564A for ; Sun, 4 Jan 2009 12:40:30 +0000 (UTC) (envelope-from petefrench@ticketswitch.com) Received: from constantine.ticketswitch.com (constantine.ticketswitch.com [IPv6:2002:57e0:1d4e:1::3]) by mx1.freebsd.org (Postfix) with ESMTP id A11A98FC0C for ; Sun, 4 Jan 2009 12:40:30 +0000 (UTC) (envelope-from petefrench@ticketswitch.com) Received: from dilbert.rattatosk ([10.64.50.6] helo=dilbert.ticketswitch.com) by constantine.ticketswitch.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.69 (FreeBSD)) (envelope-from ) id 1LJSHJ-000DIx-WE; Sun, 04 Jan 2009 12:40:26 +0000 Received: from petefrench by dilbert.ticketswitch.com with local (Exim 4.69 (FreeBSD)) (envelope-from ) id 1LJSHJ-000Gfj-UE; Sun, 04 Jan 2009 12:40:25 +0000 To: andrew@modulus.org In-Reply-To: <496011CC.2010201@modulus.org> Message-Id: From: Pete French Date: Sun, 04 Jan 2009 12:40:25 +0000 Cc: freebsd-stable@freebsd.org Subject: Re: slow zvol performance compared to files on the same pool X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 04 Jan 2009 12:40:31 -0000 > On 7.x (where ZFS is really quite broken for server use - don't waste > too much time on it) the ZVOL code did an "fsync" after every single > block write. Its a testament to your fast disks that you got as high as > 12mb/s. I don't know why your read speed was so bad, but you should try > again on 8-current as numerous fixes and improvements have happened. Ah, thatnks. That explains it perfectly. I'll re-do the read test and also give 8-CURRENT a try if I get the time. Thanks. -pete.