Slow VM Clone using SCE caused by long suspensions on COPY_WAIT
VM Clone using SIS-Clone Copy Engine (SCE) should be very fast as it does not involve any real data copy. But on ONTAP 9.5, it has been observed that SCE performance is degraded and it only provides a similar throughput as Block Copy Engine(BCE).
The majority of the delay comes from a long suspension on COPY_WAIT.
WAFL_SPINNP_COPY 71573 120.78 813
Note: In this case, average Suspend time on COPY_WAIT is about 120.78ms.
The WAFL suspension stats could be viewed from any Perfstats, or collected in a manual way:
nodeshell>priv set diag
nodeshell>wafl_susp -z // clear the wafl_susp stats
wait for a while
nodeshell>wafl_susp -w // collect the wafl_susp stats