Note about ZFS deduplication for chunked files

[nncp.git] / doc / cmds.texi

diff --git a/doc/cmds.texi b/doc/cmds.texi
index 1de83a4e8dc361f1ac0fade948fa853a905dddda..ce0855a972db3c43334c86f44e7422a0f864de53 100644 (file)
--- a/doc/cmds.texi
+++ b/doc/cmds.texi
@@ -20,6 +20,9 @@ Nearly all commands have the following common options:
     1-255 values are allowed.
 @item -node
     Process only single specified node.
+@item -via
+    Override @ref{CfgVia, via} configuration option for destination node.
+    Specified nodes must be separated with comma: @verb{|NODE1,NODE2|}.
 @item -spool
     Override path to spool directory. May be specified by
     @env{NNCPSPOOL} environment variable.
@@ -252,17 +255,16 @@ packet creation. Pay attention that if you want to send 1 GiB of data
 taken from stdin, then you have to have 2 GiB of disk space for that
 temporary file and resulting encrypted packet. You can control where
 temporary file will be stored using @env{TMPDIR} environment variable.
-Encryption is performed with
-@url{https://www.schneier.com/academic/twofish/, Twofish} algorithm, 256
-bit random key, zero IV, in
-@url{https://en.wikipedia.org/wiki/Counter_mode#Counter_.28CTR.29, CTR}
-mode.
+Encryption is performed with @url{https://cr.yp.to/chacha.html,
+ChaCha20} algorithm. Data is splitted on 128 KiB blocks. Each block is
+encrypted with increasing nonce counter.
 
 If @option{-chunked} is specified, then source file will be split
 @ref{Chunked, on chunks}. @option{INT} is the desired chunk size in
 KiBs. This mode is more CPU hungry. Pay attention that chunk is saved in
 spool directory immediately and it is not deleted if any error occurs.
-@option{-minsize} option is applied per each chunk.
+@option{-minsize} option is applied per each chunk. Do not forget about
+@ref{ChunkedZFS, possible} ZFS deduplication issues.
 
 If @ref{CfgNotify, notification} is enabled on the remote side for
 file transmissions, then it will sent simple letter after successful
@@ -401,6 +403,8 @@ Checksums:
     3: 0e9e229501bf0ca42d4aa07393d19406d40b179f3922a3986ef12b41019b45a3
 @end verbatim
 
+ Do not forget about @ref{ChunkedZFS, possible} ZFS deduplication issues.
+
 @node nncp-rm
 @section nncp-rm