Question on MDS Zoning

[mvsheik123]

Hello experts,

Simple question on Zoning-  Say 4 host servers (SRV) with HBA with 1port each and Storage ( ex:K) server with 4 ports. All connected via MDS switch.

what is the difference in the below 2 configs:

ZoneA: SRV1-port1+K port1+K port2+K port3+K port4

ZoneB: SRV2-port1+K port1+K port2+K port3+K port4

ZoneC: SRV3-port1+K port1+K port2+K port3+K port4

ZoneD: SRV4-port1+K port1+K port2+K port3+K port4

----------------------------------------------------------------

ZoneA: SRV1-port1+K port1

ZoneB: SRV1-Port1+K port2

ZoneC: SRV1-Port1+K port3

ZoneB: SRV1-Port1+K port4

ZoneE: SRV2-Port1+K port1

ZoneF: SRV2-Port1+K port2

ZoneG: SRV2-Port1+K port3

ZoneH: SRV2-Port1+K port4

List goes this way for rest of 2 servers.

I read in docs and also community experts suggestion to create 'Single initiator-single target',  but in the above scenario what makes the difference?

Thank you in advance

MS

[Walter Dey · Accepted solution]

Most storage vendors ask for single initiator - single target zoning; as you can from above, the number of zones (and therefore configuration work) is bigger, then for single initiator - multiple target zoning.

In the end, you also have to consider the limitation on # zones, .... see eg.

http://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/6_2/configuration/guides/config_limits/configuration_limits_6-2.html

To reduce the waste of hardware resources (TCAM space), Cisco introduced smart zoning.

http://www.cisco.com/c/dam/en/us/products/collateral/storage-networking/mds-9100-series-multilayer-fabric-switches/at_a_glance_c45-708533.pdf

[mvsheik123]

Hi Walter & dkester,

Thank you very much for your reply. Now I got that Single ini -> Single tar needs less permissions. I was checking the Smart zoning doc and it was mentioned that..

"SAN administrators allow servers (initiators) and storage devices (targets) in a Fibre Channel SAN to talk to each other by adding them to the same zone. In the fabric, permissions defined in this way are converted to access control entries, (ACEs) which are programmed into ternary content-addressable memory (TCAM) hardware in the switches"

So, when we define zone /zoneset and 'commit' the software automatically create ACEs and TCAM entries? What is the command to check those ACEs?

Or these need to be set up specifically on MDS switches?  I have 5 servers in total (2ports each) and one storage (with 8ports)- 4 goes to one MDS and 4 goes to other, I will be setting up with 20zones in each switch, based on 2 single initiator->single target method.

Looks like Smart zone needs 5.2.x or later mine are running 5.0. I will see if I use Smart zone by upgrading the OS.

Thank you again.

MS

[dakester · Accepted solution]

Zone Member Configuration Guidelines
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/6_2/configuration/guides/fabric/nx-os/nx_os_fabric/zone.html#pgfId-1967293
For a zone with N members, N *( N -1) access permissions need to be enabled. 

The first configruation example has 4 zones with 5 memebers each.
4 zones times 5*(5-1) = 80 access permissions.

The second configuration example has 16 zones with 2 members each.
16 zones times 2*(2-1) = 32 access permissions.

consider the ZoneA in the first configuration.
ZoneA: SRV1-port1+K port1+K port2+K port3+K port4

This says  Kport1 needs access to Kport2
           Kport1 needs access to Kport3
           Kport1 needs access to Kport4
           etc.
So access permissions are set up to accommodate storage to storage communication.
This is probably not your intent.

Smart zoning implements hard zoning of large zones with fewer hardware resources. 
http://www.cisco.com/c/en/us/td/docs/switches/datacenter/mds9000/sw/6_2/configuration/guides/fabric/nx-os/nx_os_fabric/zone.html#pgfId-2017149
 Smart zoning eliminates the need to create a single initiator to single target zones. 
By analyzing device-type information in the FCNS, useful combinations can be implemented at the hardware level by the Cisco MDS NX-OS software, and the combinations that are not used are ignored. For example, initiator-target pairs are configured, but not initiator-initiator (or storage-storage).