From owner-freebsd-fs@FreeBSD.ORG Fri Nov 6 19:34:06 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 97B071065693 for ; Fri, 6 Nov 2009 19:34:06 +0000 (UTC) (envelope-from ivoras@gmail.com) Received: from mail-ew0-f209.google.com (mail-ew0-f209.google.com [209.85.219.209]) by mx1.freebsd.org (Postfix) with ESMTP id 288488FC18 for ; Fri, 6 Nov 2009 19:34:05 +0000 (UTC) Received: by ewy5 with SMTP id 5so1338580ewy.36 for ; Fri, 06 Nov 2009 11:34:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:from:date:x-google-sender-auth:message-id:subject:to:cc :content-type:content-transfer-encoding; bh=KUHRqe16cNcLjgOovfIWGmCC0xJoqR0FvVx3O9eRqj0=; b=BUiI0AobLvAlrExOiPoVwmclgU4XWweo8uQnSPimpQahRpTAF0UBoRsMIjot5TLrSw h80hx5GwK72Vqu4cgOvBAx7keC88lMyF5vKAk48a3yI9BgT8DTI9eV0EYbQ+zdtvlJnl Y1Z1B+gDJoaal/M00jHNUH48iN+IesrfWNZnw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:from:date :x-google-sender-auth:message-id:subject:to:cc:content-type :content-transfer-encoding; b=Htw0NcgoiV/iFdouaVLVjdOHfxcaCuG/qswycWcIE6sheNAify1qVN3Flv+KJLROZg 6GGLalEMn9yzOlpPQYdd74AnVamkw8usNVbddj6nyUkzbUq5XXCQCBzElBcCx8rNIv2I 8ITwg0JjMdaz7Gp1FikNvYaCbJTb5eihR32Hc= MIME-Version: 1.0 Sender: ivoras@gmail.com Received: by 10.216.89.193 with SMTP id c43mr1429838wef.221.1257534096161; Fri, 06 Nov 2009 11:01:36 -0800 (PST) In-Reply-To: <4AF46CA9.1040904@quip.cz> References: <772532900-1257123963-cardhu_decombobulator_blackberry.rim.net-1402739480-@bda715.bisx.prod.on.blackberry> <4AEEBD4B.1050407@quip.cz> <4AEEDB3B.5020600@quip.cz> <4AF46CA9.1040904@quip.cz> From: Ivan Voras Date: Fri, 6 Nov 2009 20:01:16 +0100 X-Google-Sender-Auth: 51b74079c92339e5 Message-ID: <9bbcef730911061101h5356d2acob2ac8791afe112@mail.gmail.com> To: Miroslav Lachman <000.fbsd@quip.cz> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: freebsd-fs@freebsd.org, freebsd-stable@freebsd.org Subject: Re: Performance issues with 8.0 ZFS and sendfile/lighttpd X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Nov 2009 19:34:06 -0000 2009/11/6 Miroslav Lachman <000.fbsd@quip.cz>: > I do not understand why there are 10MB/s read from disks when network > traffic dropped to around 1MB/s (8Mbps) > > root@cage ~/# iostat -w 20 > =C2=A0 =C2=A0 =C2=A0tty =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 ad4 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0ad6 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 cpu > =C2=A0tin tout =C2=A0KB/t tps =C2=A0MB/s =C2=A0 KB/t tps =C2=A0MB/s =C2= =A0us ni sy in id > =C2=A0 0 =C2=A0 14 41.66 =C2=A053 =C2=A02.17 =C2=A041.82 =C2=A053 =C2=A02= .18 =C2=A0 0 =C2=A00 =C2=A02 =C2=A00 97 > =C2=A0 0 =C2=A0 18 50.92 =C2=A096 =C2=A04.77 =C2=A054.82 114 =C2=A06.12 = =C2=A0 0 =C2=A00 =C2=A03 =C2=A01 96 > =C2=A0 0 =C2=A0 =C2=A06 53.52 101 =C2=A05.29 =C2=A054.98 108 =C2=A05.81 = =C2=A0 1 =C2=A00 =C2=A04 =C2=A01 94 > =C2=A0 0 =C2=A0 =C2=A06 54.82 =C2=A098 =C2=A05.26 =C2=A055.89 108 =C2=A05= .89 =C2=A0 0 =C2=A00 =C2=A03 =C2=A01 96 Yes, this could limit your IO if the requests are random enough. Unfortunately I don't know how would you track down what is really going on. Maybe some tracing with DTrace? I'd tell you to use "top -m io" to see if there is a process responsible, but apparently these statistics are not updated for ZFS, which in itself may be a bug (which is why I'm crossposting to freebsd-fs).