Bruno,

I understand it's a decrypt and decompress, transfer data and then do it 
over again. I would hope that the hardware could do encryption and 
compression at line rate.
So you're thinking it's hardware and there aren't things I should change in 
bareos? I'm assuming that tape to tape copies should not spool, is that a 
reasonable assumption?

I'm seeing about 140MB/s on a newer system as well. So wasn't sure if it's 
the hba or Linux or bareos or something else.

On Thursday, April 10, 2025 at 9:07:41 AM UTC-5 Bruno Friedmann 
(bruno-at-bareos) wrote:

> Hi Jon,
>
> The encryption key is set by drive/tape so of course it is not just copy 
> that block from here to here, it has to be deciphered uncompressed and then 
> goes the inverse.
> From my maths (if correct) it look like you have 142MB/s read/write which 
> is ~50% of native speed.
> Maybe the hba is somewhat limited and can handle more than the native 
> 300MB/s one way?
>
> On Thursday, 10 April 2025 at 15:16:50 UTC+2 Jon Schewe wrote:
>
>> I have 2 LTO-8 drives and I'm executing a copy job from one to the other. 
>> I'm using hardware encryption and compression. I have spooling turned off 
>> because it's tape to tape, so I woudl expect one could just read from one 
>> tape and write to the other. The source tape has 16TB of raw data. I would 
>> expect a tape to tape copy to be reasonably fast, however I'm finding that 
>> after 24 hours I've only seen 12TB copied between the 2 tapes. 
>> Is this just how slow the tapes are? Or is there something I can 
>> reconfigure in bareos to speed this up?
>>
>

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