Date: Fri, 17 Sep 2010 14:07:33 +0300 From: Kaya Saman <kayasaman@gmail.com> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-ports@freebsd.org Subject: Re: Fwd: Tomcat6 port keeps locking up?? Message-ID: <4C934BF5.7@gmail.com> In-Reply-To: <20100917100723.GA49737@icarus.home.lan> References: <4C926418.2050407@gmail.com> <4C9328B9.4010100@gmail.com> <20100917085621.GA48570@icarus.home.lan> <4C933284.6050601@icyb.net.ua> <20100917094212.GA49319@icarus.home.lan> <4C933A85.8080703@icyb.net.ua> <20100917100723.GA49737@icarus.home.lan>
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On 17/09/2010 13:07, Jeremy Chadwick wrote: > On Fri, Sep 17, 2010 at 12:53:09PM +0300, Andriy Gapon wrote: > >> 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. >> > I trust your experience with it *much* more than mine. :-) It's very > likely that I'm basing the "ARC remains at 1400MB" claim entirely off of > what top(1) was showing under either "Inact" or "Wired". > > The terminology in top(1) for memory on BSD has always confused the hell > out of me. That might sound crazy coming from someone that's been using > *IX since 1990 and BSD since 1996, but it's true. The man page does go > over what's what, but the descriptions are short one-liners (ex. "wired > down" doesn't mean anything to me). This just circles back to my lack > of knowledge about the VM. > > Aren't there supposed to be 2 versions of 'top'?? Unix top and Linux top?? Both with slightly different handles on the representation of information? I just recall reading somewhere!!
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