The ZFS team integrated a wad of fixes this weekend, so I BFUed my personal workstation up and ran some simple/real world tests. I''d previously seen about a 40% hit building Solaris on ZFS vs. UFS on a dual-core Opteron box; that''s been corrected (and more). If you''re interested, have a look at my blog: http://blogs.sun.com/roller/page/danasblog?entry=zfs_v_ufs_performance_for Cheers Dana