I see some of the same questions come across a variety of mailing lists. Often times the questions are phrased differently, but they are essentially asking the same things over and over again. This is not a bad thing as new people are introduced to ZFS and start asking about it. I find that I am sending people to a number of links where people who know more about ZFS than I have already answered the questions. To simplify giving out all these URLs I am gathering them up here for reference in one place. Expect this list to grow as I find more good write-ups on ZFS and ZFS related topics.
These will all open in a new tab or window.
Matthew Ahrens on RAIDz stripe width
Richard Elling on MTTDL and ZFS configurations MTTDL == Mean Time To Data Loss or a relative measure of how safe your data will be
My ZFS Resilver Observations from replacing a drive in 2014
My ZFS Performance vs ZPOOL Layout results from testing I did while at a client in 2010
FreeBSD Wiki ZFS Tuning Guide FreeBSD specific, slightly dated, has some recommendations but does not fully explain them
Solaris Internals ZFS Best Practices Guide this one is very old but still has good information, even if it is Solaris specific
Solaris Internals ZFS Evil Tuning Guide this one is also very old, but still contains some very good information on how ZFS works