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

Daniel Kjar dkjar at elmira.edu
Fri Nov 4 18:35:37 UTC 2011


Interesting...  I will have to check the connection although this is 4x

On 11/ 4/11 01:50 PM, Robin Axelsson wrote:
> Yeah, for a period I had the system gobble up vast amounts of RAM 
> while running Virtualbox. I tried capping the ARC (in some config file 
> I believe, can't remember) but that didn't help. In the end I 
> discovered that this happened when the virtual machines did network 
> intensive tasks over a NAT connection and the problems disappeared 
> when I switched to bridged networking. I filed a bug report and the 
> Virtualbox team fixed the bug in version 3.2.12.
>
> On 2011-11-04 16:41, Michael Stapleton wrote:
>> Hello,
>>
>>      There is an issue running VirtualBox with ZFS. ZFS will cause
>> fragmentation of memory which is usually not a problem, but due to the
>> nature of how VirtualBox attempt to lock down continuous chunks of RAM,
>> it is a problem for VBox. If you are running VBox and ZFS, cap the ARC
>> cache...
>>
>>
>> Mike,
>>
>>
>>   On Fri, 2011-11-04 at 10:39 -0400, Daniel Kjar wrote:
>>
>>> 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
>>>>
>>
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>>
>
>
>
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-- 
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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