Re: temp files

[Colin Percival <cperciva@tarsnap.com>]

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
storage.

> 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