Date: Mon, 30 Jul 2001 21:14:21 +0200 From: Wilko Bulte <wkb@freebie.xs4all.nl> To: Matthew Jacob <mjacob@feral.com> Cc: scsi@FreeBSD.ORG Subject: Re: DLT 4000 throughput and cstream Message-ID: <20010730211421.A1475@freebie.xs4all.nl> In-Reply-To: <Pine.BSF.4.21.0107281231100.13594-100000@beppo>; from mjacob@feral.com on Sat, Jul 28, 2001 at 01:11:56PM -0700 References: <3B630DE0.FC696BC4@progroup.com> <Pine.BSF.4.21.0107281231100.13594-100000@beppo>
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On Sat, Jul 28, 2001 at 01:11:56PM -0700, Matthew Jacob wrote: > > [ -hardware trimmed- Only one list is needed ] > > > > > KB/t tps MB/s > > > 60.59 22 1.31 > > > 60.59 22 1.31 > > > 61.05 22 1.31 > > > 60.62 22 1.32 > > > 60.59 22 1.31 > > > ... > > This is about half the speed you should expect. Hm, it is about what I get on my DLT4000 drive using dump. Dump just does not keep the tape streaming. I know from experience that the DLT can do much better than this. Wilko > Testing with dump, w/wo cstream, is not helpful. You need to test with a > non-zero data generator: > > yorp.feral.com > root camcontrol devlist > <SEAGATE ST39175FC 0001> at scbus0 target 129 lun 0 (pass0,da0) > <SEAGATE ST39175FC 0001> at scbus0 target 130 lun 0 (pass1,da1) > <SEAGATE ST39175FC 0001> at scbus0 target 131 lun 0 (pass2,da2) > <SUN DLT4000 CC2D> at scbus2 target 2 lun 0 (sa0,pass3) > <HP C1537A L609> at scbus2 target 3 lun 0 (sa1,pass4) > <TANDBERG SLR5 4/8GB =09:> at scbus2 target 6 lun 0 (sa2,pass5) > yorp.feral.com > tape_pattern_tester > tape_pattern_tester: [ -v ] [ -b blksize ] [ -r blocks per file ] [ -n > number-of-files ] -f no-rewinding-tape-drive > yorp.feral.com > tape_pattern_tester -v -b 32k -r 1000 -n 5 -f /dev/nsa0 > .......Rewind Tape > ........Write Pass > EOT at File 4 Record 1000 Offset 32768 (163840000 total bytes written) > Elapsed Seconds: 60; Data Rate: 2.6MB/s > .......Rewind Tape > .........Read Pass -- | / o / / _ Arnhem, The Netherlands email: wilko@FreeBSD.org |/|/ / / /( (_) Bulte To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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