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

[Michael Stapleton]

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
> >
>