From owner-freebsd-scsi Sun Mar 29 19:53:26 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id TAA12597 for freebsd-scsi-outgoing; Sun, 29 Mar 1998 19:53:26 -0800 (PST) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fddi.Simon-Shapiro.ORG [206.190.148.2]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id TAA12517 for ; Sun, 29 Mar 1998 19:53:18 -0800 (PST) (envelope-from shimon@simon-shapiro.org) Received: (qmail 20228 invoked from network); 29 Mar 1998 20:55:45 -0000 Received: from localhost.simon-shapiro.org (HELO sendero-fxp0.simon-shapiro.org) (@127.0.0.1) by localhost.simon-shapiro.org with SMTP; 29 Mar 1998 20:55:45 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-032398 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: Date: Sun, 29 Mar 1998 12:55:45 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Ustimenko Semen Subject: RE: SDT-7000 and other DDS-2 tapes Cc: FreeBSD-scsi@FreeBSD.ORG Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On 25-Mar-98 Ustimenko Semen wrote: > On Wed, 25 Mar 1998, Simon Shapiro wrote: >> On 25-Mar-98 Ustimenko Semen wrote: >> > >> > Have somebody succesfuly used SDT-7000 under FreeBSD? >> >> Yes. Two of them in shared mode on a DPT controller. >> > Wow! And it realy gives 600kb/s (I have only 150, and not proper > capacity). Tell me, pls, is it -CURRENT, and what blocksize and density > do you use? And dmesg:) My tests hover around 1-1.2MB/Sec for CPIO or DUMP (But, important BUT below). Here is a fragment of dmesg from sendero sd80: Direct-Access 23834MB (48813696 512 byte sectors) pt5 at scbus5 target 7 lun 0 pt5: type 3 fixed SCSI 2 pt5: Processor sd88 at scbus5 target 8 lun 0 sd88: type 0 fixed SCSI 2 sd88: Direct-Access 23834MB (48812544 512 byte sectors) scbus6 at dpt1 bus 2 worm6 at scbus6 target 4 lun 0 worm6: type 4 removable SCSI 2 worm6: Write-Once st6 at scbus6 target 5 lun 0 st6: type 1 removable SCSI 2 st6: Sequential-Access density code 0x13, 512-byte blocks, write-enabled pt6 at scbus6 target 7 lun 0 pt6: type 3 fixed SCSI 2 pt6: Processor IMPORTANT BUT: The SCSI tape drive is DANGEROUSLY next to useless! If the system uses ANY block size other than 512 bytes, you will silently produce trash tapes. Here are some details: * Do NOT use dump(1). Dump uses blocking that are a multiple of 1K. This produces tapes that cannot be read; The data is trash, there are no EOF maks on the tape, etc. * CPIO must be factored with -C 512, or you will get the same trash problems. * When you run at 512 byte blocks, throughput becomes akin to RS-232C. It is very, very slow. The danger lies in the dumping/writing process NOT producing ANY indication of failure. Things just zoom along nicely. The problem arises when you try to READ the tapes. There will be nothing but trash there. BTW, My answr got delayed, as I had to dump some 30GB of data to tapes, as part of disks upgrade. It took that long to finish (4 days). ---------- Sincerely Yours, Simon Shapiro Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message