Re: LTO Ultrium
2003-01-24 12:46:13
Hello,
* Martin Oehler (martin.oehler AT gmx DOT net) [20030124 11:52] thus spake:
> Hi, Jon!
>
> Am Fre, 2003-01-24 um 16.27 schrieb Jon LaBadie:
> >
> > Maybe you hit what Gene describes in another posting today.
> > Once a tape has been written to with HW compression, the drive senses it
> > and automatically switches to HW compression regardless of settings.
>
> No, I made a mistake (see my reply to Genes posting).
>
> > What capacity were you expecting for "native", uncompressed data?
>
> I expect 100 GB. The drive specifications can be found at:
> http://www.storage.ibm.com/hardsoft/tape/3580/prod_data/g225-6854.html
> We use the internal version of the drive.
>
> > According to docs/TAPETYPE:
> >
> > The speed is currently unused.
> >
> > Is this an HP drive by any chance? ISTR they have some auto-slowdown
> > system to match scsi-bus speed.
>
> # cat /proc/scsi/scsi
> Attached devices:
> Host: scsi1 Channel: 00 Id: 04 Lun: 00
> Vendor: HP Model: Ultrium 1-SCSI Rev: N23D
> Type: Sequential-Access ANSI SCSI revision: 03
>
> If the measured size and filemark is correct, do you have an idea
> how I will be able to use the drive with 15MB/sec?
That all depends on your scsi or FC controller and pci bus.
I have 4 Seagate LTOs in a STK_L40 library connected to differential
scsi controler -- one for each drive. diff scsi because of cabling
issues: LVD is a little less sturdy than differential scsi but that's
besides the point. I have an O3800 so I can shove 60MBs doen its
throat no problem. In your case you have to ask yourself: is my pci
bus wide and fast enough to sustain 15MBs?
Here's my tapetype for my Seagate Ultrium:
define tapetype Ultrium-SGT-LTO {
comment "just produced by tapetype program"
length 101376 mbytes
filemark 0 kbytes
speed 15084 kps
lbl-templ
}
HTH,
jf
>
> Regards,
> Martin Öhler
>
>
--
"We are what we think, all that we are arises within our thoughts.
With our thoughts we make the world."
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