Re: [Veritas-bu] STK T10000 tape drive

That is true, and the number of speeds depends (am I right on this?) on how the manufactuer implemented the LTO standard. Does anyone know if there is a way to monitor/poll/capture what speed the drive is operating at a given time?

On 9/13/07, Austin Murphy <austin.murphy AT gmail DOT com> wrote:

Yes. Few drives are actually completely variable speed.   The LTO
drives from IBM can write at 5 different fixed speeds, from half speed
to full speed.

See page 55 of the PDF here: http://www.redbooks.ibm.com/abstracts/sg245946.html
It describes Dynamic Speed Matching on IBM's LTO3 drives.

IBM's TS1120 has 6 speeds.  (page 77)

This article compares the T10k and the TS1120 and mentions the write speeds.
http://www.clipper.com/research/TCG2005077.pdf

Austin

On 9/13/07, Paul Keating <pkeating AT bank-banque-canada DOT ca > wrote:
> Isn't this true for most of the high end drives?
> None of them are "variable" speed, but will write at one of 2 or 3 fixed
> speeds.
>
>
> --
>
>
> > -----Original Message-----
> > From: veritas-bu-bounces AT mailman.eng.auburn DOT edu
> > [mailto: veritas-bu-bounces AT mailman.eng.auburn DOT edu] On Behalf
> > Of Austin Murphy
> > Sent: September 12, 2007 5:23 PM
> > To: Brad Hillebrand
> > Cc: veritas-bu AT mailman.eng.auburn DOT edu
> > Subject: Re: [Veritas-bu] STK T10000 tape drive
> >
> >
> > I don't use them, but I did some research.
> > One gotcha that I came across was the writing speed.  They can only
> > write at either 120 MB/sec or 50 MB/sec.  There is no in between. Your
> > disk staging or virtual tape better be able to spit out the data at
> > one of those rates or the thing will shoe-shine like crazy.
> >
> > LTO-4 drives are likely to be easier to feed data and a lot cheaper.
> > I haven't compared prices with the hardware encryption options, but
> > w/o the encryption the drive prices are something like $5k vs. $30k.
> >
> > Also LTO-4 native capacity is 800 GB vs 500 GB for the T10k.  Both can
> > write at 120 MB/Sec.
> >
> > Austin
> ====================================================================================
>
> La version française suit le texte anglais.
>
> ------------------------------------------------------------------------------------
>
> This email may contain privileged and/or confidential information, and the Bank of
> Canada does not waive any related rights. Any distribution, use, or copying of this
> email or the information it contains by other than the intended recipient is
> unauthorized. If you received this email in error please delete it immediately from
> your system and notify the sender promptly by email that you have done so.
>
> ------------------------------------------------------------------------------------
>
> Le présent courriel peut contenir de l'information privilégiée ou confidentielle.
> La Banque du Canada ne renonce pas aux droits qui s'y rapportent. Toute diffusion,
> utilisation ou copie de ce courriel ou des renseignements qu'il contient par une
> personne autre que le ou les destinataires désignés est interdite. Si vous recevez
> ce courriel par erreur, veuillez le supprimer immédiatement et envoyer sans délai à
> l'expéditeur un message électronique pour l'aviser que vous avez éliminé de votre
> ordinateur toute copie du courriel reçu.
>

_______________________________________________
Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu