On 2020-03-24 13:30, JT Morée via tarsnap-users wrote:
> Hi,
>   I am curious about the implementation details moving data though tarsnap.   
> I realize that I can dig through the source code but it was a bit obtuse when 
> I looked.  I didn't see an answer to my question in the tips, faq, technical 
> details, etc.  
> Does tarsnap write data to disk as it creates and encrypts chunks?  If so, 
> where?  

No.  Tarsnap writes data to its cache directory when it creates archive
snapshots and at the end of creating an archive, but there's no temporary

> If not, does it stream the chunks directly to the backup servers?  In this 
> scenario I'd guess that data moves from disk through ram then across the 
> network.

Yes.  Chunks are generated in memory, compressed, encrypted, and signed, and
then uploaded to the server; typically there's < 10 MB of data "in flight".
(If there's too much waiting to be uploaded, tarsnap stops reading data from
disk until the network catches up.)

Colin Percival
Security Officer Emeritus, FreeBSD | The power to serve
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid
  • temp files JT Morée via tarsnap-users
    • Re: temp files Colin Percival

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