$Id: FAQ.Bandwidth.txt,v 1.3 2021/05/20 11:46:07 gilles Exp gilles $

This documentation is also available online at
https://imapsync.lamiral.info/FAQ.d/
https://imapsync.lamiral.info/FAQ.d/FAQ.Bandwidth.txt


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             Imapsync bandwidth used
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Questions answered in this FAQ are:

Q. What is the bandwidth used by imapsync?

Now the questions again with their answers.

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Q. What is the bandwidth used by imapsync?

R. From the host where imapsync runs, imapsync opens two imap
connections, one with the source account at host1, one with the
destination account at host2.
   
So, the global bandwidth used by an imapsync transfer is twice the
volume of the source account, one volume to download the messages from
host1, one volume to upload those messages to host2.

If the host2 is already filled with the messages, imapsync doesn't
transfer them and then the volume transferred is small, this volume is
just made up of the IMAP commands needed to identify the messages on
both sides.
   
There is no local cache of the email messages, except when a message
is very big; it is then temporarily saved locally between the download
and the upload.
   
The biggest message seen so far on the online service I call /X is
3.08 GiB while the biggest message transferred is 1.51 GiB. So I
suspect a bug here. Drop me a note if you encounter the same issue,
I'll then dig into it, ie, I'll create a 2 or 3 GiB big message and
play with it :-)


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