ZFS Storage Appliance and Solaris can see write performance degradation when filesystem is almost full

Tonight MOS has a surprising article in store for us as "Solaris 10, Solaris 11 and ZFS Storage Appliance (ZFSSA) Software may Experience Write Performance Degradation when ZFS Filesystem is Near Quota" from note ID 1985528.1 as an entire pool can lose performance if the poolset comes within 2GB of being totally used!  You can also find out what commands are used to check this, and if you are affected then see what patchsets are available so you can get patched up to prevent this from happening to you.