Re: [Veritas-bu] STK T10000 tape drive
2007-09-13 10:22:00
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 > ====================================================================================
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