Rsync push is slower compared to pull
dag at wieers.com
Wed Aug 23 19:03:23 GMT 2006
On Wed, 23 Aug 2006, wwp wrote:
> On Wed, 23 Aug 2006 14:50:39 +0200 (CEST) Dag Wieers <dag at wieers.com> wrote:
> > On Wed, 23 Aug 2006, Srinivasa Battula wrote:
> > > On Wed, 32 Aug 2006, Dag Wieers wrote:
> > > > On Wed, 23 Aug 2006, Srinivasa Battula wrote:
> > > >
> > > > > It has been observed that rsync push mode is much slower when
> > > > > compared to pull (On Identical scenarios). Building/receiving file
> > > > > list takes almost same time. But data transfer is much slower, whose
> > > > > transfer ratios are ranging from 1:3 to 1:5. On pull operation data
> > > > > transfer speed is consistently around 3.5 MB/Sec and it reached 10
> > > > > MB/Sec. However, on push the maximum it could reach is around 2
> > > > > MB/Sec and hogs around 1MB/Sec. Why is this difference? Please help
> > > > > me on this...
> > > >
> > > > Do these identical scenarios also include changing the sender and
> > > > receiver
> > > > for both push and pull ? That would be required to dismiss the network
> > > > configuration/environment as the possible cause.
> > >
> > > Source and Target remain same. The way rsync is being invoked is
> > > different.
> > My question implied to urge you to test with the sender and receiver
> > switched. And compare those results as well. You should end up with 4 sets
> > of transfer speed data.
> > Analysing that should make clear if pulling/pushing is the cause, or if it
> > is the network environment (sender/receiver).
> > Also make sure that the tests are not influenced by other factors (eg.
> > other people doing exactly the same test as yours on the same
> > network/system :)). Doing the tests multiple times during the day may make
> > it more convincing to state your case.
> Wouldn't disk-read and disk-write speeds explain or hide the difference
> sometimes, if Srinivasa does the reverse test (exchange server and client
> machines, perform the same test)? Even, hardware speeds in general?
Could be, but the difference he is now seeing could not be explained by
disks since the pull and push seems to be sending the data in the same
direction. (from the same disk to the same disk)
I was not implying that the network necessarily was the problem, but at
least reversing the direction would give much more information to analyse.
Or debunk the initial proposed cause.
-- dag wieers, dag at wieers.com, http://dag.wieers.com/ --
[all I want is a warm bed and a kind word and unlimited power]
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