[OpenIndiana-discuss] Memory drains away....

Daniel Kjar dkjar at elmira.edu
Fri Nov 4 14:39:59 UTC 2011


I have seen that in plenty of places and I 'know' it to be true but as I 
watch zfs swallow all of my ram and my server ends up stuttering (when 
it shouldn't) then I have to do something.  Although everything 
everywhere says that ZFS gives it up whenever asked many comments from 
oracle and the zfs tuning guide hint that it isn't really that good at 
giving it up.  Some processes don't know the right way to ask (exert 
pressure) etc.  Also, when ZFS was young Sun kept saying that it using 
all of the available ram was harmless but... later they figured out 
there was a bug in how it was handling the process of detecting memory 
constraints on the system and now there are known scenarios when 
limiting ZFS hunger is called for.

I was just hoping there was something else going on here with 151a but I 
see now that is not the case.

On 11/ 4/11 10:28 AM, Rob McMahon wrote:
> On 04/11/2011 13:13, Daniel Kjar wrote:
>> pmap seems to give me exactly what top tells me.
> Remember top will almost always show low free memory.  Free memory is 
> wasted memory, it gets filled by filesystem cache, zfs or otherwise, 
> and re-used when needed.  Look at e.g. `vmstat 5' to look for memory 
> issues.
>
> Rob
>

-- 
Dr. Daniel Kjar
Assistant Professor of Biology
Division of Mathematics and Natural Sciences
Elmira College
1 Park Place
Elmira, NY 14901
607-735-1826
http://faculty.elmira.edu/dkjar

"...humans send their young men to war; ants send their old ladies"
	-E. O. Wilson






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