[Beowulf] Re: OT: LTO Ultrium (3) throughput? (Steve Cousins)

David Mathog mathog at caltech.edu
Wed Jul 2 17:13:53 EDT 2008

Steve Cousins <cousins at umit.maine.edu> wrote:

> > Just under 60MB/sec seems to be the maximum tape transport read/write
> > limit.  Pretty reliably the first write from the beginning of tape was a
> > bit slower than writes started further into the tape.
> I believe LTO-3 is rated at 80 MB/sec without compression.

I just checked that.  The spec page here:



Higher performance with dynamic data rate matching - Ultrium 920 Tape
Drive 120MB/sec compressed data transfer using 2:1 compression,

Or with compression off 60MB/sec, assuming that the 120MB/s was rate
limited by the physical tape write speed and not at all by the
compression.  On the other hand, the specs for the CARTRIDGE here:


list 80MB/s uncompressed, which is the number you cited.  Also here:
they cite 80MB/s.

Do different LTO-3 drives have different maximum tape write speeds?


David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech
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