From owner-freebsd-geom@FreeBSD.ORG Wed Mar 5 16:13:11 2014 Return-Path: Delivered-To: freebsd-geom@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 4BEEE540 for ; Wed, 5 Mar 2014 16:13:11 +0000 (UTC) Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 1C902CAE for ; Wed, 5 Mar 2014 16:13:10 +0000 (UTC) Received: from compute5.internal (compute5.nyi.mail.srv.osa [10.202.2.45]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 6DE2F2119D for ; Wed, 5 Mar 2014 11:13:00 -0500 (EST) Received: from web6 ([10.202.2.216]) by compute5.internal (MEProxy); Wed, 05 Mar 2014 11:13:00 -0500 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=message-id:from:to:mime-version :content-transfer-encoding:content-type:subject:date:in-reply-to :references; s=smtpout; bh=UBC3R9KxjekoHN9OolPwJ84ER10=; b=NyP03 9ozS9PAahFRhII7gNMtwuK+Mx50UPrL1VDxF3456zr35b2cUPLLqWdDcXZuAIV/p vt3e7w727HzAeeq/jHHMR6Qu9X2chktWFAZZRca89wGYelO/RvMvEoRMcggGS4Ks 3Mt1yVHAmtpwKEBsVFrguMomRQNrwOgQYrKcL8= Received: by web6.nyi.mail.srv.osa (Postfix, from userid 99) id 597F528A4CB; Wed, 5 Mar 2014 11:13:00 -0500 (EST) Message-Id: <1394035980.8640.90922737.615AFA56@webmail.messagingengine.com> X-Sasl-Enc: 4QaC8oSdySYiOZwsODjGJf+hIvwg2gzwwXhY9gHN24Nu 1394035980 From: Mark Felder To: freebsd-geom@freebsd.org MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain X-Mailer: MessagingEngine.com Webmail Interface - ajax-4527a23f Subject: Re: HAST local read performance? Date: Wed, 05 Mar 2014 10:13:00 -0600 In-Reply-To: References: X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Mar 2014 16:13:11 -0000 On Wed, Mar 5, 2014, at 8:08, Karl Pielorz wrote: > > Hi, > > I have a couple of FreeBSD 10 systems I've setup HAST on - this seems to > work well, but I've noticed the read performance of local /dev/hast/* > devices is around half of the normal raw device? > > e.g. a dd from an SSD as /dev/da0 nets around 220Mbyte/sec - the same dd > run against the same device when setup with hast (i.e. /dev/hast/disk1) > only nets around 110Mbyte/sec. > > I realise another layer is going to affect performance (and this may just > be the price you have to pay) but is there anything likely tunable for > this? > > If I fail the other node (so I'm running the test against a 'degraded > primary') it's still as slow [as you'd kind of expect, as reads were/are > only local] > > I've setup ZFS on top of the hast devices - again this seems to work OK, > but you can really see the performance difference when doing a pool scrub > on hast backed devices vs. the raw ones... > Which HAST replication mode are you using? Fullsync? Do you have atime enabled on that filesystem? I'd expect it to act like a local disk without any significant penalties unless you're doing writes and they're waiting to be synced before the next read.