IOM6 to IOM12 upgrade, performance results?

[Maurice-FreeOnes]

Hello,

I am thinking about upgrading the complete FAS2750 stack we have from IOM6 to IOM12. Does anybody have any experience with the performance increase when doing this? The SAS and SSD disks we have do all support 12 Gb/s, only not the SATA shelf. I am wondering or it's worth the money to upgrade all IOM6 to IOM12 modules. In theory there should be a 100% perofrmance increase isn't it?

Regards, Maurice

[SpindleNinja]

the shelf is still a DS2246 though right?     the backplane runs at 6.  

[paul_stejskal]

I've only seen 6Gb/s be a bottleneck on high end AFFs. You have to be pumping over 1 GB/s through them disks to even begin to hit limits. Don't forget you have 4 PHYs, so you get 24Gb of througput functionally, or about 3 GB/s per stack.

[Maurice-FreeOnes]

This is on of our stacks:

XXXXXX::> storage shelf show

Module Operational
Shelf Name Shelf ID Serial Number Model Type Status
----------------- -------- --------------- ----------- ------ -----------
1.0 0 XXXXXXXXXXXXXXX DS224-12 IOM12E Normal
1.1 1 XXXXXXXXXXXXXXX DS2246 IOM6 Normal
1.2 2 XXXXXXXXXXXXXXX DS2246 IOM6 Normal
1.3 3 XXXXXXXXXXXXXXX DS4246 IOM6 Normal
1.4 4 XXXXXXXXXXXXXXX DS224-12 IOM12 Normal
4.0 0 XXXXXXXXXXXXXXX DS224-12 IOM12E Normal
4.1 1 XXXXXXXXXXXXXXX DS2246 IOM6 Normal
4.2 2 XXXXXXXXXXXXXXX DS2246 IOM6 Normal
4.3 3 XXXXXXXXXXXXXXX DS4246 IOM6 Normal
4.4 4 SHFGD1703000417 DS224-12 IOM12 Normal
10 entries were displayed.

Our SAS disks can run on 12 Gb/s, our SATA have a 6 Gb/s limit.

It's the plan to replace all IOM6 for IOM12 if that brings a performance boost.

[aborzenkov]

I wonder if such configuration is supported. According to current documentation, only one transition between IOM6 to IOM12 is allowed and here there are two transitions.

[Daniel_66]

As per "12Gb SAS SE Presentation_v1.5.1.pptx" in Field portal, multiple stack transitions between IOM6 and IOM3 are permitted with ONTAP 9.2P1 or later.

[SpindleNinja]

You're talking 6 and 12 though.  where did 3 come in to play here? 

from the 12GbSAS deck - A maximum of one transition from 12Gbps to 6Gbps modules is supported

What does config advisor say when you run it at this system? 

[Maurice-FreeOnes]

1225017 - ONTAP support for mixing IOM6-based and IOM12-based shelves in the same stack

https://mysupport.netapp.com/site/bugs-online/product/ONTAP/BURT/1225017

[SpindleNinja]

Right "  Only one speed transition is allowed."   like their example: 

Controller <-> IOM6 <-> IOM6 <---> IOM12 <-> IOM12 <-> Controller

From your output it looks like you're doing: 

controller -> 12 -> 6 -> 6-> 12 -> controller  

[aborzenkov]

---

@SpindleNinja wrote:

from the 12GbSAS deck - A maximum of one transition from 12Gbps to 6Gbps modules is supported

---

It is a bit unclear whether embedded IOM (IOM12E) is counted here (it says "external stack" about entry systems). Also it seems the primary use case for lifting this restriction is extending existing IOM6 stacks by IOM12 shelves. So I am not sure if even IOM12E - IOM12 - IOM6 - IOM6 would be valid ("IOM6 CIRCLE ports must be used for connection to IOM12 ports" and when going from IOM12 to IOM6 we connect IOM6 with SQUARE port ...).

So it amounts to - is IOM12E - IOM6 speed transition or simply (IOM6) stack attachment?

[SpindleNinja]

Fair point.   

I wonder what AIQ Config advisor will say. @Maurice-FreeOnes have you run config advisor against this? 

[Maurice-FreeOnes]

I first have to upgrade ONTAP and will then do the check and get back here with the results.