ONTAP Hardware

MP-HA with active-active cluster



I am searching for a detailed cabling diagram for a active-active cluster  with Multipath HA .. , It should be a diagram which clearly shows which cable going to where ,  Like it should show IN/OUT port of shelfs , not just a line pointing there.

I have attached the best diagram i found on net .

But if you are doing cable it that way , it makes lots of confusion . For example (please refer to the diagram ) Loop 3 and Loop4 cables to filer A last shelf .. where they suppose to connect whethere both the IN port of the shelf (MOD A/MOD B) are already occupied by shelf to shelf cables ..

Appriciate all help




There is no fixed cabling. There are some rules that should be followed, they are described in standard documentation. Otherwise you are free to use anything that agrees with those rules ☺


OK , rule says :

Note: The last disk shelf has no cable connected to the Channel A Output  port.
# Using the correct cable type for a disk shelf-to-contro

ller  connection, connect the Channel A Output port to a Fibre Channel port  on the partner node (Node 2).
I was in a impression that Out ports of disk shelfs are for connections going out from shelf not for the connection comming in .....
Does it mean that i can connect shelf OUT Ports to fiber adapter of the head ........ !!!!!!!!!!!!!!!


Well, using both channels is exactly what MP in MP-HA is about ☺

So rules are correct. You connect A-IN and B-OUT to one head and B-IN and A-OUT to another head. This gives you full redundancy.


Ok , It will be great help , if somebody post a Detailed diagram (somebody made for their own reference) to remove all confusion .



Cabling the last shelf in a stack for MPHA causes a lot of people confusion.  All you need to remember is it's a mirror image - left/right and up/down - of what you did on the first shelf. For example:

FAS1 connects to the A I/O module's IN port of shelf 1

FAS2 connects to the B I/O module's IN port on shelf 1

The shelves are then cabled together going from IN to OUT port of each I/O module

If shelf 4 is the last shelf in the stack:

FAS1 connects to the B I/O module's OUT port of shelf 4

FAS2 connects to the A I/O module's OUT port of shelf 4

The shelves are connected to each other using an A path and a B path so you need to connect each controller to the A and B path.  That's why FAS1 goes "in" the A path on shelf 1 and comes "out" the B path on shelf 4.

As mentioned previously, the ports you select depends on the system configuration so there is no set system port-to-shelf port list.  However, if you read the Storage Subsystem FAW there is a lengthy description of an algorithm NetApp engineers use to determine the sequence of ports to use.   https://fieldportal.netapp.com/viewcontent.asp?qv=1&docid=9866

It's also important to note - the primary connection (to shelf 1) and the return/failover connection (on the last shelf) must be either between the motherboard ports and an HBA or between two HBAs.  Systems like the FAS3100 series with no onboard SAS ports would need two HBAs to do MPHA on SAS shelves.  If the primary and return connection are both on the motherboard or a single HBA then that does not meet MPHA cabling specifications (the ONLY exception to the rule is the FAS2040).  You may find this KB article on common MPHA cabling errors useful because it diagrams the cabling (with port IDs) and then explains why it's wrong.


As always, verify your cabling with the WireGauge tool every time you make a change to the cabling.


Thanks so Much ..... I got almost all the information ...

Just one last request ..


i am not able to get to this link , i logged in as Customer ..

Can you please provide in other format like as Word document .. that will be gr8

Thanks Again