SAP HANA Fiber Channel Storage Connector - Where and How?

You've done the SAP HANA certification with SP7 contents, you learned that HANA can natively connect to block based storage, and that the HANA NameServer can manage the mount and unmounts of the storage volumes, as well as the unattended failover of HANA nodes through the SCSI-3 Persistency Group Reservations.

But you don't know how to get the storage connector, neither how to configure it.

          Where can I find the HANA storage connector and its scripts?

Well, the storage connector comes with the SAP HANA Kernel as of SP5, so you don't need any additional package. Also the scripts that are called by the name server also come with the SAP HANA Kernel.


          How does the configuration of the HANA storage connector for FC works?

The administration guide for the "SAP HANA Fiber Channel Storage Connector" can be found in attach to the SAP Note: 1900823

Download it here: https://service.sap.com/sap/support/notes1900823


          Why would you want to use block access to the HANA persistency devices?

There are two main reasons that relate with latency and reliability.

In regards to latency, it benefits the overall HANA performance that the write latency of the log blocks of 4K and 16K is the best possible. And FC access to block storage provides the best latency in regards to SAN based storage. Here I've seen normal arrays providing latencies usually bellow 500 micro seconds, with some even going bellow 400 micro seconds.

As for reliability, as many SAP notes can confirm, when you share the disk volumes of HANA in a Scale-Out cluster on a FileShare, it's challenging to implement proper fencing mechanisms that prevent having a failed node and the standby node both writing to the same volume, which would end in data corruption.

SCSI-3 Persistency Group Reservation is the mechanisms mission critical clustering software has been using to protect database clusters for years. The beauty here is that instead of needing any type of clustering software, in the case of HANA, the Master NameServer takes care of handling the failover of the failed nodes to available standby servers through the usage of this block API (this is the popular name for SAP HANA Fiber Channel Storage Connector).

So for High Availability purposes, there is no need for any additional software. HANA kernel already brings this functionality natively.

This solution provides a robust failover clustering implementation leveraging a well proven mechanism providing the most efficient communication protocol that is Block over Fiber Channel.


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DID YOU KNOW: that the python scripts that SAP uses for SAP HANA connection to block storage were initially developed together with EMC engineers?

EMC Engineers worked on this project together with SAP, and as of SP5 SAP included their code in the standard SAP HANA kernel release, being now SAP the owner of that code and the one responsible for its support and evolution.

Today this connector (Block over Fiber Channel) is available to all other storage manufacturers, and is the one most used for SAP HANA Tailored Datacenter Integration certification of Enterprise Storage, having Block over FC become the standard in SAP HANA storage connection.

This is one of the reasons why EMC was one of the first hardware partners to get a Enterprise Storage System certified under the TDI Program.



Check out the current list of certified storage systems for SAP HANA TDI at: http://scn.sap.com/docs/DOC-48516

Find out more about EMC Solutions for SAP HANA at: https://community.emc.com/docs/DOC-17151