DLPX-70512 Long zio delays likely caused by Linux IO scheduler write throttling logic (#233)

Author: pzakha

files/common/lib/udev/rules.d/60-dlpx-schedulers.rules

@@ -0,0 +1,6 @@
+#
+# Delphix: this setting disables the write throttle algorithm that is used in
+# the Linux IO scheduler for all block devices as we've seen problems with it.
+# We explicitly disable it for zvols as it doesn't seem to apply to them anyway.
+#
+ACTION=="add|change", SUBSYSTEM=="block", KERNEL!="zd*", ATTR{queue/wbt_lat_usec}="0"