ZFS is all about performance (many levels of caching, pre-fetch, …) and
memory consumption :-)
Here are my last links about ZFS
internals, it’s worth a read if you plan to use ZFS on large productions :
The slides of Adam Leventhal’s talk for the OpenSolaris Storage Summit : ZFS, Cache, and Flash
c0t0d0s0.org : a very good explanation of the ARC cache : most recently used pages, most frequently used pages and their ghosts lists Some insight into the read cache of ZFS - or: The ARC and the (http://www.c0t0d0s0.org/archives/5329-Some-insight-into-the-read-cache-of-ZFS-or-The-ARC.html)[writing side](http://www.c0t0d0s0.org/archives/5343-Insights-into-ZFS-today-The-nature-of-writing-things.html#extended)
The arc_summary.pl tool is very useful for analysis, made by Ben Rockwood with the kstat counters.
Also by Ben Rockwood : ZFS in the Trenches is an overview of a real-life-production usage of ZFS : interesting counters and tuning hints at the different levels (monitoring, ARC, ZIL, Physical I/O, backup & replication), useful tools, and experience sharing. A must-read !
And before anything, always refer to the ZFS Best Practices Guide of solarisinternals.com
If you have some interesting links about ZFS too, share them with us in the comments !