Go for ONTAP 9.3 minimum: iSCSI Performance Improvements

If iSCSI is your MAIN SAN protocol, then you must think about upgrading your controllers to 9.3 minimum:

Reason: The entire iSCSI stack was re-written for ONTAP 9.3. This was done to increase parallelization so that iSCSI processing could take advantage of the higher core controllers that NetApp has been shipping recently.

Prior to the re-write some iSCSI processing was single threaded and therefore had a bottleneck where processing was dependent on the speed of a single processor core. By refactoring the NetApp software iSCSI target to multi-threaded iSCSI processing iSCSI (ONTAP 9.3) is now able to take advantage of numerous CPU cores each of which can concurrently process iSCSI threads.

In addition, increasing multi-threading, other improvements, while perhaps not as substantial, were also included. These include reducing or eliminating locks and context switches and other incremental improvements. The improvements in iSCSI performance seen from this refactoring of iSCSI software target are substantial with the largest improvements seen on larger controllers that have more cores that can be used to concurrently process iSCSI threads.

Compared to 9.2: 2.6x Performance increase @1ms

TR:4080