I believe you will have trouble getting
more than 5-6 megabytes a second out of Hp's store.
We recently switched to DLT-7000s, with a native speed
of 5mb a second, so should get maybe 10-15 mb a second
with the easily compressible data.
However, the HP staff admits that Store (and Turbo store)
has a bottle neck making it impossible to achieve speeds much
more than 5-6mb/sec.
DLT7000s (and DLT-8000s) require dedicated Fast Wide SCSI channels.
Since our HP989 can only have 3 channels without an
expensive expansion chassis add-on, our disc performance
has suffered since we gave up one controller to the DLT.
On your 979, you can add an option for 2 more internal slots
so you can have a total of 5 16 Fast Wide SCSI (although
with today's 160mb/second Ultra SCSI, I hardly call 20mb/sec
fast!)
Performance is a little better than when we did 4 DDS-2 drives
in parallel, but not too much more.
Perhaps, with an I/O expansion, and using 2 DLT drives, running
completely separate backups, you could double the performance.
If and when LTO is supported, it is going to need much better
software to support it! I have heard Orbit's backup product
can run a DLT at full speed but have no personal experience
with it.
Also, the new DLT-1 drives are just coming out, which are much cheaper,
but not compatible with other DLTs, which is of little concern
to some, and a big problem if you have existing DLT drives.
I believe the DLT1 is slower, but may be a better match to
the slower hardware.
Since you can get 3 of the DLT-1s for the price of a DLT8000, it
might be the way to go. They may allow more than one per controller,
since their native transfer rate is slower. It would be worth looking
into .... perhaps some early customer can tell us how DLT1s work on
an HP3000. I would be curious if they could work (perhaps via an
adapter) with the old 8 bit SCSI interfaces as used for DDS drives.
I have several of these free on my computers, and you always could
use the built-in one as well. Even if it only performed on par
with a DDS-3 drive, the media holds 40gb uncompressed, versus
12 for DDS-3.
Then again, DDS-4, with 20GB native, and a higher transfer speed,
might be the cheapest solution should HP ever support them on
the HP3000. I have heard rumors that some people have managed to
get DDS-4 drives running on HP3000s.
DLTs are supposed to be much more reliable than DDS,
and I think it is true.
Older, 20GB DLT-4000s are fairly cheap on the used market,
and I believe these can work on the slower 8 bit interfaces.
If you don't have any spare 16bit controllers, using a pair
of these on their own controllers might be much faster and
more reliable than using DDS drives. Most HP3000s have spare
slots for the half sized 8 bit cards, and they are real cheap
on the used market. The built-in 8 bit interface, normally used
for the internal DDS drive and not much more, would support
at least one DLT drive (probably not two running in parallel,
though.)
While waiting for Ultrium, used DLT-4000 might be a cost-effective
choice. The new DLT1s also might work well.
Any reports on running DDS-4 on HP3000s?
Do DLT-4000s work well on the 8 bit interfaces, or do
they really need their own dedicated 16bit channel?
Anyone getting much more then 6mb/second on a DLT7000-8000?
If so, how? and what did it cost?
Any idea if the new Ultrium drives will ever work on
current generation HP3000s, or will they require the
new systems with PCI interfaces?
-----Original Message-----
From: Neil Harvey [mailto:[log in to unmask]]
Sent: Friday, December 01, 2000 8:59 PM
To: [log in to unmask]
Subject: Re: [HP3000-L] Disk capacity on an 979KS
From the PDF file (which took a while for me to download) :-
http://www.hp.com/storage/pdf/NETDESK_ULT230.pdf
tape speed 4.1 minutes per second
Yes folks, promising technology indeed!
Neil
-----Original Message-----
From: Neil Harvey [mailto:[log in to unmask]]
Sent: Saturday, December 02, 2000 6:54 AM
To: [log in to unmask]
Subject: Re: Disk capacity on an 979KS
Greetings
Backup is becoming a real issue on our Health Care sites - even on a small
site, capacities run into 80 - 90 GB.
We use DDS3 now, sometimes in parallel, and try to keep backup times down
below 2 - 3 hours, but this becoming unworkable.
With Hardware Compression, we generally get a 3 -1 ratio, so we can fit up
to 36GB on a single media.
I don't think DDS4 is supported on K series boxes (our favourites).
I'm looking for a quantum leap in backup speed.
At HPWorld I saw LTO (Linear Tape Open) drives and media.
From HP's website at http://www.hp.com/tape/ultrium/index.html :-
"The ultra-fast HP SureStore Ultrium 230 stores up to 200 GB* of data on a
single tape at a sustained transfer rate of 30MB/s*. With ultimate
reliability and ease of use in mind, the rugged design builds on the best
existing technologies to create a new level of data protection."
Now, this sounds better - If I can get 3-1 on these babies, I'll have 300 GB
per stick, all within 2 hours. And the technology is at it's very beginning
- so we should expect the same exponential advances as we saw with DDS - 1
through 4.
Question is, are they real, and do they work on K series HP3000's?
Of course, I won't retire until there is Liquid Memory Technology (LMT)
available on tap, and we can just pour data into LMT Vessels :)
Regards
Neil
-----Original Message-----
From: Stan Sieler [mailto:[log in to unmask]]
Sent: Saturday, December 02, 2000 2:03 AM
To: [log in to unmask]
Subject: Re: Disk capacity on an 979KS
Re:
> The Fast Wide SCSI limit is 15 devices per channel,
> although this is not recommended for performance reasons.
> I don't think HP currently supports drives larger than
> the 36GB ones, which would limit you to 540GB per controller.
MPE/iX 6.5 supports 72 GB drives, which (at 15 per channel) would
be 1 TB per controller!
That question about backing it up just got harder :)
> You can add several I/O expanders, with their own card cage,
> and an additional HP-PB expansion, etc. (The HP-PB only goes
> to 32mb a second, so several SCSI channels per PB can keep
> it mighty busy.)
<plug> DiskPerf, from Allegro, could be used to test the
I/O capacity of a system.
</plug>
Stan Sieler [log in to unmask]
www.allegro.com/sieler/wanted/index.html www.allegro.com/sieler
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