I don't believe there's a way to measure this directly without abusing dtrace.
Some things that may be helpful:
gstat(8) - Geom device statistics, can show you raw disk activity / workload
Doesn't directly measure latency though.
ioping - Lets you measure latency from userland (you could run it & log/chart the results)
Downside: Adds load to do the test, passes through the VFS layer, and can't test the underlying drive unless you reserve a partition for it to use.
I don't believe there's a way to measure this directly without abusing dtrace.
Some things that may be helpful:
gstat(8)- Geom device statistics, can show you raw disk activity / workloadDoesn't directly measure latency though.
ioping - Lets you measure latency from userland (you could run it & log/chart the results)
Downside: Adds load to do the test, passes through the VFS layer, and can't test the underlying drive unless you reserve a partition for it to use.