On Mon, 11 Sep 2006 at 11:41am, Jon LaBadie wrote
On Mon, Sep 11, 2006 at 11:28:29AM -0400, Joshua Baker-LePain wrote:
On Mon, 11 Sep 2006 at 11:23am, Jon LaBadie wrote
That tape write rate is too slow. Native speed for an LTO3 drive is
rated at ~80MB/s.
I think it is really an LTO2.
The OP said 400GB, but was probably referring to marketing capacity.
Well that makes sense. Even in that case, though, 30MB/s is still too
slow, especially given that he's using hardware compression.
Really, my tapechart (from Fuji), says Ultrium 2 is 30MB/s for HP drive
and 35 for an IBM drive.
*sigh* That's what I get for not checking the specs. I recalled
(incorrectly) that LTO had been scaling speed with capacity the whole
time. You're right -- rated native speed for LTO2 is 30MB/s.
I also suspect his data is already pretty random, possibly compressed
by whatever moved it to his server. Note only 200GB of amanda data
filled the tape.
Well, a bit more, but not enough to really affect the speed.
So it looks like the problem really is dumping to holding disk, which
shouldn't be necessary if this is all on the same server.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
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