Ok. That means your DAT40 is working at the fastest speed possible in
DDSIII mode with the DDSIII (125M) tapes. So even the faster throughput
that would come with using DAT40 (150M) tapes is not available through your
connection. So, if your tape has enough capacity for the backup, your setup
is optimum and cost-effective.
Denys
-----Original Message-----
From: Gilles Schipper [mailto:[log in to unmask]]
Sent: Thursday, September 27, 2007 10:16 PM
To: Denys Beauchemin; [log in to unmask]
Subject: RE: [HP3000-L] dat40
At 11:06 PM 2007-09-27, Denys Beauchemin wrote:
>Interesting. You should know that if you are using 125Meter tapes, you are
>actually using the DAT40 as a DDSIII device, not a DAT40 (same if you use
>the 125M tapes in a DAT72.)
>
>The reason for your increased throughput is due to the tape drive turning
>the tape faster, not because it is writing as a DAT40. The drive would
>operate faster with a 150M tape.
Not in our experience.
We did extensive testing of the backup environment.
There was absolutely no difference in elapsed
time when using a 150M tape compared to a 125M
tape - in both cases to the same dat40 drive.
We wanted to be able to justify the immediate
purchase of new 150M tapes, but the results of our tests did not support it.
Also, I should point out that Christian's
original question pertained to the use of the dat40 on a k-class 3k.
I would have been glad to provide capacity
statistics for a k-class, but I did not have access to them.
In any case, the capacity statistics would be
identical for a k-class and n-class (or any class).
>I would love to read about Neil's experiences. (He's from South Africa,
not
>New Zealand, btw.)
Sorry, Neil. My bad.
> One should be able to store a lot of data in such an
>autoloader.
>
>Thanks for the great info.
>
>Denys
>
>-----Original Message-----
>From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On Behalf
>Of Gilles Schipper
>Sent: Thursday, September 27, 2007 9:56 PM
>To: [log in to unmask]
>Subject: Re: [HP3000-L] dat40
>
>The following statistics are associated with a
>HP3000/N4000 full backup to a dat40 tape drive utilizing a dds3 tape.
>
>(dat40-native 150-meter tapes are not used
>because of existing high available inventory of
>125-meter tapes and no perceived benefit of use
>of higher-capacity tapes, since full backup fits entirely on a single
tape).
>
>Total backup file data on media: approx. 33gb
>Total compressed data on media: approx. 10gb
>
>So, given the same compression ration of better
>than 3 to 1, in this example we could assume an
>additional 20% of file data before we would need
>to purchase 150-meter tapes or suffer a second media for the backup.
>
>A dds3 (aka dat24) tape has a native capacity of
>12gb; dds4 (aka dat40), 20gb; dds5 (aka dat72), 36gb.
>
>I believe Neil Harvey in New Zealand has been
>utilizing a dat40 autoloader which satisfies a
>hands-free backup requirement for multi-media backups.
>
>If you're still lurking, Neil, please correct me if I'm wrong.
>
>A very good reference to the existing and
>emerging DDS/DAT technology is available at www.datmgm.com.
>
>At 09:17 PM 2007-09-27, Denys Beauchemin wrote:
> >The DAT40 is at the limit of what an SE-SCSI HBA can generate, which is
why
> >the DAT72 is no faster. The DAT40 is able to run at less than its rated
> >speed without falling out of streaming mode. I think it's a combination
of
> >the size of the buffer and its ability to adjust.
> >
> >I wonder, Gilles, how much are you able to store on a cartridge? Do you
> >approach 40GB?
> >
> >Denys
> >
> >
> >-----Original Message-----
> >From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
Behalf
> >Of Gilles Schipper
> >Sent: Thursday, September 27, 2007 10:24 AM
> >To: [log in to unmask]
> >Subject: Re: [HP3000-L] dat40
> >
> >At 08:46 PM 2007-09-26, Hawkins, Jim (HP, MPE/iX Lab) wrote:
> > >(top post warning).
> > >
> > >Of Denys two suggestions the 50-68 cable to an
> > >SE-SCSI HBA is more likely to provide a basic
> > >connection. The HVD/LVD converter would not
> > >work on k-Class as there are actually some
> > >driver restrictions in the NIO F/W SCSI HBA
> > >driver that prevent one from configuring a DDS
> > >as connected to a A28696A HBA bus (at least as far back as 6.5).
> > >
> >The 50-68 cable would be the one if connecting
> >directly to the se-scsi port of the k-class mfio card.
> >
> >If daisy-chaining via other se-scsi devices, the
> >cable may need to change accordingly to match the connection points.
> >
> >
> > >At the same time "connect ability" does not mean
> > >"advisability" and never "supportability".
> > >
> > >o We didn't test the DAT40 on S900/NIO systems
> > >because its peak I/O bandwidth (6.0 MB/sec
> > >Asynchronous) was projected to exceed the
> > >capabilities of the SE-SCSI HBA (technically 5.0
> > >Megabytes/sec but really closer to 4
> > >MB/S). Historically it is not a good idea to
> > >run tapes at slower than rated speed as it
> > >causes the tape to drop from streaming mode into
> > >start/stop mode and excessive wear and/or bad
> > >performance result. Many tape drives do
> > >implement variable speed streaming but it wasn't clear that the DAT40
was
> >one.
> > >
> > >o We never certified any LVD-SCSI interface
> > >peripherals on the NIO-SE-SCSI HBA. Though all
> > >Wide LVD devices are technically supposed to be
> > >able to RUN (READ/WRITE/REWIND) narrow & SE-SCSI
> > >it is never advisable depend upon manufacturer
> > >actually testing all device functionality in
> > >such a hobbled mode. Additionally newer devices
> > >may spit out "SCSI Standard" information that very old drivers will
choke
> >on.
> > >
> > >o No idea what the PDC would do if you tried to
> > >boot from a CSLT on this device. . .
> > >
> > >This means that DAT40 is NOT supported by HP via
> > >SE-SCSI on S900 NIO systems (9x8,9x9,99x &
> > >earlier). Works fine and is supported by HP on A/N-Class.
> > >
> > >So, I'd advise you only use this kind of set-up
> > >to write data you are willing to lose ;-)!, OR
> > >at least make sure your back-up application
> > >vendor is willing to support you. YMMV. . .
> >Supported or not, it WORKS.
> >
> >In fact, it more than works.
> >
> >Not only can you boot from it, on a k-class it
> >performs significantly faster than a dds3 drive.
> >
> >On an N-class, a full backup using STORE can
> >complete in one-third the time when compared to a dds3.
> >
> >The bottom line is that the dat40 shines on
> >virtually all HP3K models, with performance
> >advantage over the dds3 increasing with increasing HP3K cpu speed.
> >
> >Also, the dat72 (aka dds5) also works very well
> >with the 3k - although its performance is almost equal to the dat40.
> >
> >
> >
> > >Jim Hawkins
> > >MPE/iX I/O Architect
> > >
> > >
> > >-----Original Message-----
> > >From: HP-3000 Systems Discussion
> > >[mailto:[log in to unmask]] On Behalf Of Denys Beauchemin
> > >Sent: Wednesday, September 26, 2007 12:32 PM
> > >To: [log in to unmask]
> > >Subject: Re: [HP3000-L] dat40
> > >
> > >Hello Christian, long time.
> > >
> > >I believe the DAT40 is an LVD device which would require you to connect
>it
> > >via a 68 to 50 pin cable with high-bit termination or to a 68 bit SCSI
>port
> > >on the 3000 using a converter to allow you to switch from HVD (HP3000)
to
> > >LVD or SE (DAT40).
> > >
> > >Denys
> > >
> > >-----Original Message-----
> > >From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
>Behalf
> > >Of Christian Scott
> > >Sent: Wednesday, September 26, 2007 1:20 PM
> > >To: [log in to unmask]
> > >Subject: [HP3000-L] dat40
> > >Importance: High
> > >
> > >Hi,
> > >
> > >
> > >
> > >I need to find out if I can connect a dat40 on a hpe3000 k-class
server,
>if
> > >so what are the step involve.
> > >
> > >
> > >
> > >Thanks,
> > >
> > >
> > >
> > >Christian Scott
> > >VP - Development & CTO
> > >201 Rue Laurier Est
> > >Suite 630
> > >Montréal, Québec
> > >H2T 3E6
> > >
> > >Tel: 514-273-0008 x118
> > >Fax: 514-273-0199
> > >Email: <mailto:[log in to unmask]> [log in to unmask]
> > >
> > >Web: <http://www.softvoyage.com/> www.softvoyage.com
> > >
> > >
> > >
> > >
> > >* To join/leave the list, search archives, change list settings, *
> > >* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
> > >
> > >* To join/leave the list, search archives, change list settings, *
> > >* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
> > >
> > >* To join/leave the list, search archives, change list settings, *
> > >* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
> > >
> > >
> > >
> > >--
> > >No virus found in this incoming message.
> > >Checked by AVG Free Edition.
> > >Version: 7.5.488 / Virus Database:
> > >269.13.32/1032 - Release Date: 2007-09-26 8:20 PM
> >
>
>---------------------------------------------------------------------------
>-
> >---------------------
> >Gilles Schipper
> >GSA Inc.
> >HP System Administration Specialists
> >300 John Street, Box 87651 Thornhill, ON Canada L3T 7R4
> >Voice: 905.889.3000 Fax: 905.889.3001
> >email: [log in to unmask] web: http://www.gsainc.com
>
>---------------------------------------------------------------------------
>-
> >---------------------
> >
> >* To join/leave the list, search archives, change list settings, *
> >* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
> >
> >* To join/leave the list, search archives, change list settings, *
> >* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
> >
> >
> >
> >--
> >No virus found in this incoming message.
> >Checked by AVG Free Edition.
> >Version: 7.5.488 / Virus Database:
> >269.13.32/1032 - Release Date: 2007-09-26 8:20 PM
>
>---------------------------------------------------------------------------
-
>---------------------
>Gilles Schipper
>GSA Inc.
>HP System Administration Specialists
>300 John Street, Box 87651 Thornhill, ON Canada L3T 7R4
>Voice: 905.889.3000 Fax: 905.889.3001
>email: [log in to unmask] web: http://www.gsainc.com
>---------------------------------------------------------------------------
-
>---------------------
>
>* To join/leave the list, search archives, change list settings, *
>* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
>
>
>
>
>--
>No virus found in this incoming message.
>Checked by AVG Free Edition.
>Version: 7.5.488 / Virus Database:
>269.13.32/1032 - Release Date: 2007-09-26 8:20 PM
----------------------------------------------------------------------------
---------------------
Gilles Schipper
GSA Inc.
HP System Administration Specialists
300 John Street, Box 87651 Thornhill, ON Canada L3T 7R4
Voice: 905.889.3000 Fax: 905.889.3001
email: [log in to unmask] web: http://www.gsainc.com
----------------------------------------------------------------------------
---------------------
* To join/leave the list, search archives, change list settings, *
* etc., please visit http://raven.utc.edu/archives/hp3000-l.html *
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