[Discuss] rsync question

[Cy Schubert]

--------
Five will get you ten that your system is servicing interrupts. Top will 
tell you if most of your CPU utilization is system or user state. As to 
addressing this, there is no easy answer. Niceing it to run it under a 
lower priority won't help because, as I suspect, your system is servicing 
interrupts.


-- 
Cheers,
Cy Schubert <Cy.Schubert at komquats.com> or <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  http://www.FreeBSD.org

	The need of the many outweighs the greed of the few.


In message <CAAyoHDqWDFEXV0q_Rt4X2o=WTrbMwCafMkbrFvN+aH2ZunssWQ at mail.gmail.c
om>
, "Andrew M. B. Boktor" writes:
> While rsync is doing its thing, open htop and take a look at what's
> happening.
> rsync will often do a lot of hashing on a partially transferred file (the
> hashing happens on both server and client) in order to figure out if the
> already transferred portion is not corrupt.
> Also the -z option tells rsync to compress before transfer.
> Both compression and hashing will hog your CPU. Hashing will hog your disk
> too.
> 
> Andrew
> 
> On Tue, Jul 28, 2015 at 11:04 PM, John Blomfield <jabfield at shaw.ca> wrote:
> 
> > I have a theory about an issue that I suspect is caused by rsync. As part
> > of my backup procedure I sometimes have a large 45GB file to rsync from my
> > computer hard drive to a backup USB hard drive. I have noticed that this
> > grabs about 80% of the CPU and prevents viewing videos on the computer and
> > streaming them over my network. When this happens I have abort the rsync
> > process but I still can't view videos. My theory is that rsync is caching
> > the partly transferred 45GB file and this is the same cache storage space
> > used by the video as a buffer. That is there is not enough buffer left for
> > the vidoe. I also notice that when rsync is restarted even after a reboot
> > it quickly gets back to where it was when it was aborted. Usually the
> > problem clears up after a couple of reboots. Is this theory correct or is
> > this all coincidence?
> >
> >
> > John
> >
> > --
> > John Blomfield
> > Delivered by Thunderbird Email on Linux OpenSuse-KDE4
> >
> >
> >
> > _______________________________________________
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> >
> 
> 
> 
> -- 
> Andrew Boktor