From owner-freebsd-hardware Sun Jul 29 14:33:26 2001 Delivered-To: freebsd-hardware@freebsd.org Received: from mail.inka.de (quechua.inka.de [212.227.14.2]) by hub.freebsd.org (Postfix) with ESMTP id 2B0C937B401 for ; Sun, 29 Jul 2001 14:33:23 -0700 (PDT) (envelope-from daemon@mips.inka.de) Received: from kemoauc.mips.inka.de (uucp@) by mail.inka.de with local-bsmtp id 15QyBd-0005Df-00; Sun, 29 Jul 2001 23:33:21 +0200 Received: (from daemon@localhost) by kemoauc.mips.inka.de (8.11.4/8.11.1) id f6TKW5L45628 for freebsd-hardware@freebsd.org; Sun, 29 Jul 2001 22:32:05 +0200 (CEST) (envelope-from daemon) From: naddy@mips.inka.de (Christian Weisgerber) Subject: Re: DLT 4000 throughput and cstream Date: Sun, 29 Jul 2001 20:32:03 +0000 (UTC) Message-ID: <9k1rs3$1chj$1@kemoauc.mips.inka.de> References: <3B62D0CF.27C12B9@we.lc.ehu.es> Originator: naddy@mips.inka.de (Christian Weisgerber) To: freebsd-hardware@freebsd.org Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Jose M. Alcaide wrote: > I am pipelining dump(8) to cstream (ports/misc/cstream), using this > command line: FWIW, when I tried cstream some time ago it didn't appear to live up to its author's claims. Personally I use misc/buffer for this purpose. > However, I am getting what a I think is a too low transfer rate > (compression is enabled on the DLT unit). This is what I get with > iostat(8): > > sa0 > KB/t tps MB/s > 60.59 22 1.31 I get 1.4 MB/s with compression _disabled_. > Is this the expected throughput for a DLT 4000? Well, does the tape stream? I.e. does it run continously, or does it drop back to stop-and-go mode? I can't get my DLT4000 to stream properly with compression enabled. I have no idea why. The disk delivers 8+ MB/s, disk and tape are on different SCSI buses. I dump(8) to a holding partition and transfer the complete archive from there to tape. I'm left with the conclusion that the DLT4000's compression engine can't keep up. -- Christian "naddy" Weisgerber naddy@mips.inka.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message