To add to that, it would seem that UFS is more likely to 'give pages back' before things to to crap and system performance tanks versus ZFS.
It might just be me, and the 'feel' of it, but it still feels to me that the system needs to be under more memory pressure before ZFS gives pages back. This could also be because I'm typically using systems with either > 128GB, or <= 4GB of RAM, and in the smaller case, not having some headroom costs me... The additional CPU usage is most notable on smaller systems, with a less than generous clock speed / performance per clock. One of my boxes at home is an Athlon 1Ghz. It blows as a ZFS server for many reasons, one of then being CPU required for the checksums etc. That being said, UFS + SVM is crap for pretty much the same reason. Bottom line, from a 'dumb user' (that's me) perspective is that if you have a reasonably current CPU (Something like a Dual core, 2Ghz+) and sufficient memory (for me, it seems to be 4GB minimum for the OZ, my applications, some virtualisation stuff and ZFS) that it can keep up with the IO demands, ZFS rocks. If you are on old old hardware, most software based raid / volume manager operations are going to be pretty crappy. I'm in the process of putting together a new play box that'll be AMD Quad Core, 8GB memory and some newish SATA-II disks. I'll let you know how that goes... It should smoke... Cheers! Nathan. Bob Friesenhahn wrote: > On Mon, 9 Jun 2008, Dick Hoogendijk wrote: > >> ZFS is called crap by FreeBSD people, because of the great memory hog >> and high CPU usage. I know it zfs uses more memory the a UFS system, >> but can somebody give some hints about how much the difference is? > > I don't see any high CPU usage here. The ARC cache grows based on > current I/O activity (and can grow quite large) but can be tuned down > (at least in Solaris) if necessary. As far as the memory consumed by > ZFS vs UFS it is pretty difficult to tell since UFS can be quite > aggressive at caching as well. The UFS caching is often hidden by > system tools and reported as unused memory. > > ZFS definitely prefers a 64-bit kernel. > > Bob > ====================================== > Bob Friesenhahn > [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
