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

Jon Aquilina eagles051387 at gmail.com
Thu Jul 3 23:58:31 PDT 2008


this is slightly off topic but im just wondering why spend thousands of
dollars when u can just setup another server and backup everything to a
raided hard drive array?

On 7/2/08, 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. Testing it on
> our HP unit in an Overland library I get:
>
> WRITE:
>
> dd if=/dev/zero of=/dev/nst0 bs=512k count=10k
> 10240+0 records in
> 10240+0 records out
> 5368709120 bytes (5.4 GB) copied, 71.8723 seconds, 74.7 MB/s
>
> READ:
>
> dd of=/dev/null if=/dev/nst0 bs=512k count=10k
> 10240+0 records in
> 10240+0 records out
> 5368709120 bytes (5.4 GB) copied, 69.2487 seconds, 77.5 MB/s
>
> I used a 512K block size because that is what I use with our backups and it
> has given optimal performance since the DLT-7000 days.
>
> Good luck,
>
> Steve
> ______________________________________________________________________
>  Steve Cousins, Ocean Modeling Group    Email: cousins at umit.maine.edu
>  Marine Sciences, 452 Aubert Hall       http://rocky.umeoce.maine.edu
>  Univ. of Maine, Orono, ME 04469        Phone: (207) 581-4302
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-- 
Jonathan Aquilina
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