ZFS Pool Performance⚓︎
ZFS Takes a Performance Penalty During High Utilization⚓︎
ZFS Pools should be kept below 80% utilization for best I/O performance. Once a volume goes over 80% the file system writes slow down and performance will become an issue. If the volume is primarily read you may be able to take the volume up to 95% utilized, but writes will still be impacted.
Also note that this performance hit impacts resilvering. This means that if you attempt to add a larger disk to the pool to increase the size, you may impact the already degraded I/O on the volume further.
