--bwlimit how to
Tue, 03 Sep 2002 22:06:38 -0700
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>>>>> "T" == trevor <email@example.com>
>>>>> wrote the following on Tue, 3 Sep 2002 13:33:09 -0500 (CDT)
T> You might also want to put a URL to a source for cstream in there
T> as only people who've read your list archives will have a clue
T> what we're talking about.
T> The only other option would be to put cstream in the ssh command
T> rdiff-backup --remote-schema 'ssh %s '\''cstream -v 1 -t 10000 |
T> rdiff-backup --server'\' localsrcdir
T> I'm wracking my brain trying to determine what the difference
T> between that and the last option would be, if any.
If ssh compression is enabled, this could result in rdiff-backup being
limited by a much lower real network rate than intended... If you are
making comparisons, remember that by default rdiff-backup enables ssh
compression (this is overridden by the --remote-schema option).
T> So if you want to update your FAQ, use the 2 examples I've marked
T> with *'s as they, in theory, should be the best methods.
Hmm, because of the compression issue your first way still seems more
flexible to me.
T> I'm only guessing at this, as I'm hard pressed to find an easy
T> method of testing this. However, this would make it extremely
T> bursty and somewhat contrary to what I want to achieve with
Perhaps you could mail the author? Doesn't qualify as a "test", but
hopefully will result in valid information.. :)
T> This leads me to a suggestion. rdiff-backup should either
T> multithread or fork into 2 processes so that while a file's data
T> is transferring, it can be calculating the next file and getting
T> it ready for potential transfer. That way you keep the data pipe
T> busy at all times, instead of the think - transfer - think -
T> transfer burstiness it seems to do now.
T> I'm not saying that this is imperative or you should triple the
T> complexity of the code to do this... (I am a programmer and know
T> how this stuff works)... but if you ever do a rewrite it would be
T> something to think about.
Yep, perhaps for version 2.0. I considered threads when initially
writing rdiff-backup but decided to keep it simple. Note that the
burstiness can at most result in a factor of two speed reduction
compared to the optimal (always thinking+always writing).
If I were adding threads I'd add more than two I think, so that
multiprocessor systems could work on multiple files simultaneously.
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