FI to NetApp direct attach via FC

[harrygranger]

Hi,

We have a small POD which has followings:

UCS 5108

FI 6248 (two)

FEX 2208

B200M3

NetApp 2240

Plan is to connect NetApp directly via FC.

Are there any cons (pros) doing this.

Thanks,

Harry

[gkumark]

Hi Harry,

May we know what is the UCS firmware version?

Well, FC direct attach works fine with UCS in any version, but there are some restrictions. If you are using the UCS firmware prior to 2.1, then you would need an upstream SAN switch like MDS which can push the zone database to the Fabric Interconnect. So here even when you have the direct attached storage, you are not eliminating the need for SAN switch.

If you are using firmware 2.1, its great! You can just connect your storage directly to the FI through FC Storage port and you can do the zoning in the FI directly!! Note that, the FI should be running in FC switch mode for this. Here you don't need an upstream SAN switch to push zone config.

You can refer to

http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/gui/config/guide/2.1/b_UCSM_GUI_Configuration_Guide_2_1_chapter_010111.html for configuration.

Pros:

======

++ No need of upstream SAN switch

++ No multiple hops for the FC traffic

Cons:

======

++ If you want to connect any other non UCS server to the storage, you would have to use another storage port to connect to the upstream switch

++ If you have very less UCS servers, then you might be under utilizing the storage ports.

-Ganesh

[harrygranger]

Hi Ganesh,

Thanks for the reply. We are using firmware 2.1.

Only one FAS2242 with two controllers.

Plan is each FI connect both controller for availiability and redundancy.

Do you have any advice on that?

Thanks,
Harry

[gkumark]

Hi Harry,

Yes, your plan sounds good. The connections would be something like this.

FAS Controller A Port 1 ---> FI-A Port x

FAS Controller B port 1 ---> FI-A Port y

FAS Controller A Port 2 ---> FI-B port x

FAS Controller B Port 2 ---> FI-B port y

Also, make sure that you include both target WWPN in the SAN connection policy. This would ensure redundancy.

-Ganesh

[harrygranger]

Hi Ganesh,

Thanks again for your reply.

Do you know NetApp controller (FAS-2240-2 A) can do port channel across controller?

On UCS side, we should use port channel since pinning is not used if FI is in switch mode, right?

Thanks,

Harry

[gkumark]

Hi Harry,

When you have the FI in FC Switch mode, you don't need any pinning to be done. All the FC traffic from all the HBA's will be switched from the FI to the FC Storage ports depending on the zoning how you have done. Even if you have static pinning done, it will be ignored when you have FI in FC switch mode. Refer to

http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/gui/config/guide/2.1/b_UCSM_GUI_Configuration_Guide_2_1_chapter_011000.html

About port channel support on FAS-2240-2A, I am not really sure about this.

-Ganesh

[harrygranger]

Hi Ganesh,

Is zoning is for a safegurad or a requriement?

Sorry for the dumb question, I have no prior storage experience and just started learning it.

Thanks,

Harry

[gkumark]

Hi Harry,

Well in the UCS version 2.1 which you are running, if you are using the FI in FC switch mode, you must do the zoning. It is a requirement. Default/Open zoning was supported in version prior to UCSM 2.1. This means all can see all. What I mean is that all the server initiators can see all the storage targets connected. We have had issues with this, so, in 2.1 we have default zoning to be Implicit Deny, which means nobody can see nobody. So, if you don't do zoning, then your storage will not be accessible.

You can refer to https://supportforums.cisco.com/thread/2185462 for more details

In General, zoning is done to make sure that only initiators that are zoned with the right target to see the storage. So, without zoning all the servers can access all the targets even if your intention is to have some servers to access only some specified target ports.

Hope this answers your question.

-Ganesh

[harrygranger]

Hi Ganesh,

Thanks again. I am truly appreciated for your help and learned a lot.

More questions here if you have time to answer:

-our plan is to install UC applicaitons, CUCM, UC, Presence, UCCX etc. About 10 servers plus ESXi, total maybe about 16 servers. They all will sit on NetApp storage.

-Are there any performance issues if we create 1:1 zoning for initiator and target?

-Are there any other method instead of zoning?

- Does Cisco has any "best practices" for FI direct attached to Storage via FC? (I can only find FlexPod papers which call for external Fabric switch.)

Thanks,

Harry

[gkumark]

Hey Harry,

To answer your questions, 16 servers accessing same storage shouldn't cause any problem at all.

-Are there any performance issues if we create 1:1 zoning for initiator and target?

[Ganesh] 1:1(Single Initiator - Single Target)  zoning means you just zone 1 HBA with 1 Storage target port. If you have multiple HBA's from the same server in same fabric, then you can zone each HBA with each storage target for redundancy. UCS also provides an option to have single Initiator Multiple Targets zoning. Consider you have a server which has HBA 1 and 2 in Fab A and HBA 3 and 4 in Fab B. Also consider you have 2 NetApp targets port A0 and Port B0 on Fab A and Port A1 and Port B1 on Fab B. Then your zoning should be something like this.

Fab A:

Zone 1: HBA1 + port A0 + port B0

Zone 2: HBA2 + port A0 + port B0

Fab B:

Zone 1: HBA3 + port A1 + port B1

Zone 2: HBA4 + port A1 + port B1

This way you have redundancy. And note that this will not cause any performance issues.

-Are there any other method instead of zoning?

[Ganesh] Well, if you have in UCS FI in FC Switch mode (in Version 2.1) , then zoning is a must. You don't really have any other option.

-  Does Cisco has any "best practices" for FI direct attached to Storage  via FC? (I can only find FlexPod papers which call for external Fabric  switch.)

[Ganesh] Well, I didn't find any best practice guide specific to Direct Attached storage. However, few things I can point out.

1. Have redundancy. Have 1 port from each storage controller (Controller A and B) connected to each FI and have them zoned accordingly.

2. Create SAN connection policy(in UCS) separately for Fab A and Fab B. Make sure that SAN connection policy for Fab A has only the targets which are connected to Fab A and so with Fab B

3. Note that all General Best Practices for SAN connectiivty holds good here as well.

-Ganesh