What is the block size algorithm

Renaud Pelissier renaud.pelissier.numvision at gmail.com
Wed Sep 15 09:53:57 MDT 2010


First of all, thank you for this great software of rsync. If is extremely
flexible and powerfull.
(my only regret is that i could not find a version for windows dealing
properly with charsets in the files' name, might be patched in a future
version of cygwin? anyway this is not the subject here [?]).

I would like to know how, in the version 3, is computed the default
I found an old post about this saying it was :

The closest 2^k approximation of N/10 000, and inside the range 700 -> 16
> 384.

But running a test on version 3,  I computed an estimate of the block size
for a 1.9Go file:

N = 1 950 368 768
> Received = 310 851
> AvBlockSigSize ~= 8.09 Byte/Block (from some other tests i made)
*BlockSize = 310 851 / 8.09 ~= 38 424*

So 38 424 is not in the range and is not far from sqrt(N)?

Could anyone tell me what is the actual implementation in the last release
of Rsync?

Best regards,

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