Fwd: Tomcat6 port keeps locking up??
freebsd at jdc.parodius.com
Fri Sep 17 09:42:15 UTC 2010
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?
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
More information about the freebsd-ports