Fwd: Tomcat6 port keeps locking up??

[Andriy Gapon]

on 17/09/2010 12:42 Jeremy Chadwick said the following:
> On Fri, Sep 17, 2010 at 12:19:00PM +0300, Andriy Gapon wrote:
>> on 17/09/2010 11:56 Jeremy Chadwick said the following:
>>> I don't think you understand how Solaris's VM behaves with ZFS.  It
>>> behaves very differently than FreeBSD.  On Solaris/OpenSolaris with ZFS,
>>> you'll see the ARC taking up as much memory as possible -- but unlike
>>> FreeBSD (AFAIK), when a userland or kernel application requires more
>> ^^^^^^^^^^^^^^^^^
>>> memory, the Solaris kernel dynamically releases portions of the ARC.
>>
>> Can you please explain that "unlike" part?
> 
> When ZFS was first introduced to FreeBSD, I was given the impression
> from continual posts on the mailing lists that memory which was
> allocated to the ARC was never released in the situation that a userland
> program wanted memory.
> 
> An example scenario.  These numbers are in no way accurate given many
> other things (network mbufs, UFS and VFS cache, etc.):
> 
> - amd64 system has 2GB physical RAM (assume ~1920MB usable)
> - vm.kmem_size="1536M" + vfs.zfs.arc_max="1400M"
> - Heavy ZFS I/O results in ARC maxing out at ~1400MB
> - Userland application runs, requests malloc() of 1024MB
> - Userland gets 384MB from physical RAM, remaining 640MB from swap
> - ARC remains at 1400MB
> 
> Is this no longer the case?
> 

I am not sure if this has even been the case :-)
It is definitely not the case now.

-- 
Andriy Gapon