Re: [Networker] maximum speed to tape using bigasm and /dev/zero

using LTO-1 we see (iostat) consistent speeed of 22 MB/s with bigasm, 
therefore compresion is aporx 1.5:1, as Davina said LTO-2 are 30-35 MB/s 
so your 55-65 MB/s is around what I would expect. If you have seen LTO-2 
speeds quoted at 70 MB/s that would be with 2 to 1 compression.

On Thu, 27 Apr 2006 12:47:23 +0100, Davina Treiber 
<DavinaTreiber AT PEEVRO.CO DOT UK> wrote:

>Jespers, Bart wrote:
>
>>
>> if we use Bigasm to test the speed of the link and devices, does this 
generate random data (non-compressable) or data which still can be 
compressed?
>> if we use (without networker) the unix "dd" command to send data 
from /dev/zero to tape, this data should be highly compressable?
>>
>> however using both described methods above, I do not succeed in writing 
more that 55-65MB/s to a IBM LTO2 taped drive comming from a solaris 9 
(4CPU, 8GB ram) host. the SAN is fully 2 Gbs.
>> I measured this using the nsrio utility (written by D Stes) which I 
found on the web.
>>
>> I thought that the max speed of a LT02 was at least 70MB/s and even 
maybe up to 140MB/s?
>>
>> what kind of max speeds have you attained with LT0 1, 2 or 3?
>>
>
>LTO-2 native write speed is 35 MB/s. If you are seeing 55-65 MB/s you're
>doing fairly well. I have only rarely seen better than that.
>
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