14 May
2007
14 May
'07
3:45 a.m.
At 9:39 PM -0500 5/13/07, Jim Leonard wrote:
My concern is that it takes nearly two hours to fill a
DLT IV (35GB)
tape, regardless of which drive I use or HBA settings I configure.
The Quantum drive averages 4168 kB/s; the SUN drive is slower and
averages 3355 kB/s. Are these times normal? With such large
capacities per tape, I would have assumed they could be filled
faster... They are reporting a 10MB/s speed, why am I getting only
4MB/s?
I'd say the speeds you got on the Quantum drive are pretty darn good,
and even the Sun drive isn't bad. Check the quantum site and see if
they still have the manuals available to download, and check what
they list as speeds for these drives. Back when we were using these
with them attached to either Auspex fileservers or Sun Ultra 2's, we
typically saw 1.5-3MB/sec speeds.
Actually the slow speeds of a DLT7000 can be nice, as it is far
easier to keep these drives streaming than something like an SDLT600.
I believe O'Reilly publishes a book on backups that has some good
tips on getting max performance out of these drives. It has been a
long time, and I doubt I still have my notes for tweaking Solaris to
work with them.
BTW, I have a Quantum DLT7000 hooked up to my VMS box, it works quite
nice, I've never bothered to check the speeds, but it's quite bad, do
to the old slow SCSI-DIFF card it's plugged into. It has helped save
my bacon at least once.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
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