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 j...@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB | _______________________________________________ freebsd-ports@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-ports To unsubscribe, send any mail to "freebsd-ports-unsubscr...@freebsd.org"
