LTO4 is rated at 120MB/s max speed, which comes out to just under 1gbit/sec
(1gbit/s = 125MB/s). I normally reserve 1gbit for each LTO4 drive. (i.e. 4
drives on a 4gb HBA)
I do see 110+MB/s streaming on those guys. (using topas -T on AIX, so not sure
about the accuracy)
Regards,
Shawn
________________________________
Shawn Drew
> -----Original Message-----
> From: ADSM-L AT VM.MARIST DOT EDU [mailto:ADSM-L AT VM.MARIST DOT EDU]
> Sent: Tuesday, February 12, 2013 12:04 PM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Re: [ADSM-L] 1 GBit FC sufficient for tape library?
>
> Another thought: You really want to avoid the LTO4 drives dropping out of
> streaming mode, even if 1Gb/s is enough bandwidth to theoretically move
> the amount of data you need to move. I believe LTO4 will operate down to
> 30-40MB/s. Worth checking, since I'm not sure, but I'm pretty sure you can
> drop as low as 40MB/s and still stay in streaming mode. Once you drop out of
> streaming mode, your throughput will go in the dumper, and you won't get
> anything close to 1Gb/s throughput.
>
> At 10:15 AM 2/12/2013, Michael Roesch wrote:
> >Hi Stefan,
> >
> >one quick question: what are the numbers you are using for your
> >calculation?
> >
> >Did you convert 240 MB/s into Gigabit/s?
> >
> >Thanks
> >
> >Regards,
> >Michael
> >
> >
> >
> >On Tue, Feb 12, 2013 at 1:01 PM, Stefan Folkerts
> ><stefan.folkerts AT gmail DOT com>wrote:
> >
> >> Yes, two LTO4 drives would not be happy at all behind a 1Gb/s HBA,
> >> even two 1Gb/s HBA's are not enough to fully utilize the drives.
> >> I would imagine you could also run into driver/firmware issues with
> >> this combination since it's a very strange one but then again....it
> >> would probably work just slow.
> >>
> >>
> >> On Tue, Feb 12, 2013 at 12:34 PM, Michael Roesch
> >> <michael.roesch AT gmail DOT com>wrote:
> >>
> >> > Hi Stefan,
> >> >
> >> > the drives are LTO4 ones. So the HBA would be the bottleneck
> >> >
> >> >
> >> > On Tue, Feb 12, 2013 at 11:36 AM, Stefan Folkerts <
> >> > stefan.folkerts AT gmail DOT com
> >> > > wrote:
> >> >
> >> > > If it is LTO1 or LTO2 you would be OK, if it is LTO3 or higher
> >> > > you are limiting your drivers with your HBA.
> >> > >
> >> > >
> >> > > On Tue, Feb 12, 2013 at 10:39 AM, Michael Roesch
> >> > > <michael.roesch AT gmail DOT com>wrote:
> >> > >
> >> > > > Hi all,
> >> > > >
> >> > > > we have an old HP MSL 6030 with two drives that share one 1
> >> > > > GBit FC
> >> > port.
> >> > > > Would that be enough to use with TSM? I have a feeling that says
> "no"
> >> > > but I
> >> > > > couldn't find any minimum FC requirements.
> >> > > > Anyone having more info? Maybe even an IBM technote?
> >> > > >
> >> > > > Thanks
> >> > > >
> >> > > > Regards,
> >> > > > Michael Roesch
> >> > > >
> >> > >
> >> >
> >>
>
>
> --
> Paul Zarnowski Ph: 607-255-4757
> CIT Infrastructure / Storage Services Fx: 607-255-8521
> 719 Rhodes Hall, Ithaca, NY 14853-3801 Em: psz1 AT cornell DOT edu
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