From owner-freebsd-scsi@FreeBSD.ORG Mon Jun 25 19:55:09 2012 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7D9E3106564A; Mon, 25 Jun 2012 19:55:09 +0000 (UTC) (envelope-from j@uriah.heep.sax.de) Received: from uriah.heep.sax.de (uriah.heep.sax.de [213.240.137.9]) by mx1.freebsd.org (Postfix) with ESMTP id 09AB68FC0C; Mon, 25 Jun 2012 19:55:08 +0000 (UTC) Received: by uriah.heep.sax.de (Postfix, from userid 107) id 2A06F37; Mon, 25 Jun 2012 21:55:07 +0200 (MET DST) Date: Mon, 25 Jun 2012 21:55:07 +0200 From: Joerg Wunsch To: Holm Tiffe , "Kenneth D. Merry" , freebsd-scsi@freebsd.org Message-ID: <20120625195507.GO2291@uriah.heep.sax.de> References: <20120601124338.GU2358@deviant.kiev.zoral.com.ua> <20120601125824.GV2358@deviant.kiev.zoral.com.ua> <20120606170640.GA98428@nargothrond.kdm.org> <20120625135543.GA58915@beast.freibergnet.de> <20120625155316.GA37535@nargothrond.kdm.org> <20120625193138.GB82032@beast.freibergnet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120625193138.GB82032@beast.freibergnet.de> X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E X-GPG-Fingerprint: 5E84 F980 C3CA FD4B B584 1070 F48C A81B 69A8 5873 User-Agent: Mutt/1.5.20 (2009-06-14) Cc: Subject: Re: Kernel panic in FreeBSD-8.3 from UFS X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Joerg Wunsch List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Jun 2012 19:55:09 -0000 As Holm Tiffe wrote: > ..., but the performance is somewhere below > the basement: > > 0: 0x1a:DLTapeIV(20GB) variable 81633 IDRC > 1: 0x1a:DLTapeIV(20GB) variable 81633 IDRC > 2: 0x1a:DLTapeIV(20GB) variable 81633 IDRC > 3: 0x1a:DLTapeIV(20GB) variable 81633 IDRC > --------------------------------- > Current Driver State: at rest. > --------------------------------- > File Number: 0 Record Number: 0 Residual Count 0 > # dd if=/dev/zero of=/dev/sa1 bs=64k count=10000 > 10000+0 records in > 10000+0 records out > 655360000 bytes transferred in 125.909593 secs (5205005 bytes/sec) I don't think 5 MB/s is a poor value for a DLT-2000. On a DLT-8000 (with wide SCSI), I get a little more than 10 MB/s provided the data source is fast enough. > It think the DLT drive should be streaming while writing 64K Blocks from > /dev/zero, shouldn't it? No, it moves back and forward all the time. Turn off hardware compression, the drive cannot compress your zeros as fast as you want. > This thing is reading even slower than writing, the Drive makes pauses of > almost 10 seconds between the really short runs. That's indeed poor. -- cheers, J"org .-.-. --... ...-- -.. . DL8DTL http://www.sax.de/~joerg/ NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)