From owner-freebsd-stable@FreeBSD.ORG Mon Feb 19 21:10:04 2007 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 834E416D6A8 for ; Mon, 19 Feb 2007 21:10:04 +0000 (UTC) (envelope-from volker@vwsoft.com) Received: from frontmail.ipactive.de (frontmail.maindns.de [85.214.95.103]) by mx1.freebsd.org (Postfix) with ESMTP id 429DD13C494 for ; Mon, 19 Feb 2007 21:10:03 +0000 (UTC) (envelope-from volker@vwsoft.com) Received: from mail.vtec.ipme.de (Q7cff.q.ppp-pool.de [89.53.124.255]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by frontmail.ipactive.de (Postfix) with ESMTP id B36E2128841; Mon, 19 Feb 2007 22:09:57 +0100 (CET) Received: from [192.168.16.3] (cesar.sz.vwsoft.com [192.168.16.3]) by mail.vtec.ipme.de (Postfix) with ESMTP id B3CCF2E5F2; Mon, 19 Feb 2007 22:09:51 +0100 (CET) Message-ID: <45DA121E.1040803@vwsoft.com> Date: Mon, 19 Feb 2007 22:09:50 +0100 From: Volker User-Agent: Thunderbird 1.5.0.9 (X11/20070119) MIME-Version: 1.0 To: Kris Kennaway References: <45D9FD35.6040702@vwsoft.com> <20070219195143.GA42379@xor.obsecurity.org> In-Reply-To: <20070219195143.GA42379@xor.obsecurity.org> X-Enigmail-Version: 0.94.0.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-VWSoft-MailScanner: Found to be clean X-MailScanner-From: volker@vwsoft.com X-ipactive-MailScanner-Information: Please contact the ISP for more information X-ipactive-MailScanner: Found to be clean X-ipactive-MailScanner-From: volker@vwsoft.com Cc: freebsd-stable@freebsd.org Subject: Re: getting garbage faster using FreeBSD? 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: Mon, 19 Feb 2007 21:10:04 -0000 On 02/19/07 20:51, Kris Kennaway wrote: > On Mon, Feb 19, 2007 at 08:40:37PM +0100, Volker wrote: >> The tape sits there since 48 hours writing a block of data every >> other minute and still didn't fill up the tape completely. The >> system this is running on is a P-4 3GHz machine using FreeSBIE 2.0 >> (6.2-RELEASE based). >> >> I suspect this to be a slow /dev/random. > > This sounds odd to me, I get 18-20MB/sec sustained read performance > from /dev/random on this 2GHz system, which is probably faster than > your tape write speed. Hmm, so this might be the tape drive(r)? I'll check this out as soon as I'm going to write to hard disk. I'm going to make some tests with /dev/random to get the real speed. >> Is there any chance to speed up /dev/random? Would a hifn >> accelerator card help here to get FreeBSD produce garbage faster? >> >> As there is medical data on all media I really need garbage >> (/dev/zero wouldn't be enough for data security as this might get >> recovered). > > Neither would a single pass with /dev/random, but you presumably knew > this. Yes, I know... I would like to run 5 or more passes if it's not that slow. Do you think playing with randoms' sysctl interface might influence performance? Does /dev/random automatically re-seed from time to time or is it seeded at boot time only? Thx, Volker