Re: how to recycle Inact memory more aggressively?

From: olli hauer <ohauer_at_gmx.de>
Date: Tue, 15 Mar 2016 19:41:29 +0100
...

>> Just a point I've bought up elsewhere...
>> I've, if I recall, wrecked several filesystems (although EIDE) using
>> rsync at the normal bus rate, and sometimes
>> thumbdrives with whatever filesystem type on them.
>>
>> I settled on --bwlimit=1500,  max for unattended  rsync usage and
>> almost every day
>> use --bwlimit=700.

It happened also on VM's where the host is connected via FC to the storage
but only on the FreeBSD VM's.


>> The latter enables several resource-intensive processes ( music,
>> classical music videos, svn, pkg, browsing, etc) to
>> proceed apace concurrently on the desktop (SATA not EIDE) with nary a
>> hang nor slowdown.

I don't have any *NIX system with a gui, only around 110+ headless systems
and halve of them are running FreeBSD.


> I have no real idea what any of that is about, but before it turns into
> some kind of "rsync is bad" mythology, let me just say that I've been
> using rsync to copy gigabytes of backup data every day for years now. 
>  I've never had any kind of problem, especially system responsiveness
> problems, until this increased swapfile activity thing started
> happening on 10-stable in the past few months.
> 
> To reiterate: rsync is not in any way at fault here, and any suggestion
> that the unresponsiveness should be "fixed" by screwing around with
> rsync parms that have worked fine for a decade is just something I
> completely reject.
> 
> I'm sure I'd see the same kind of increased swapping with ANY process
> that read and wrote gigabytes of data in a short period of time.  And
> that's what this thread is about:  What has changed to cause this
> regression that multiple people are seeing where lots of IO now drives
> an unusual amount of swapfile activity on systems that used to NEVER
> write anything to swap?

All those systems are running already for years, for me it looks more
like a missing *free* (memory leak).

Looking at the net/rsync history the last update was in Dec. 2015. Perhaps
it is worth to test net/rsync r359474 for a while to get a comparsion, but
Gary reported the issue by using `cp' and not rsync.

-- 
olli
Received on Tue Mar 15 2016 - 17:38:11 UTC

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