On Wed, 18 Apr 2012, Craig Sanders wrote:
however, zfs works much better if you give it entire disks rather than partitions. in particular, it can disable write barriers and get much better performance. IIRC it can't do that with partitions because it doesn't know what else may be writing to the disk.
making zpools from partitions does work, but is very strongly discouraged.
There is the problem that Swap over ZFS may not work (when under stress). The reason is similar to the Linux and Swap over NFS problem. http://kerneltrap.org/Linux/Swap_Over_NFS "The problem with swap over network is the generic swap problem: needing memory to free memory." The same applies to Swap over ZFS because the ARC is not integrated into the Virtual Memory Management. If it is a "storage only" it shouldn't be a problem, you just limit ARC to use most of the RAM (leave enough for the NFS/samba/AFS servers) and ARC should handle it safely without adding additional stress to the "rest" (I believe). Overall, don't be stingy with RAM and you are much happier. Otherwise it may be a good idea to use a SSD for root and swap (If you have swap on it you may put root on it as well, just to save you the hassle). Regards Peter