ISCSI Storage with UCS-B

[Hythim Ali El Hadad]

Hi,

I need to get ISCSI storage for my UCS-B

It is first time I deal with ISCSI

I hear about iscsi switch. But when reading about it I found that I can use my Nexus7k or 3850 . Also I see that I can connect the array to the FI directly .

Also I see the storage array is connected with 2 Ethernet ports without any special scsi cables .

Also Can I make about 8 boot LUNS for my servers . then Shared data LUNs for the servers also. I think it is ok.

Please confirm my concerns above and if there is any other concerns.

Thanks

Haitham

[Kirk J]

Greetings.

iSCSI uses a TCP protocol (port 3260) and just runs over regular Ethernet.

It is usually best to get connectivity setup and working before trying to enable jumbo frames, iSCSI auth, etc

You'll need to figure out how you actually want to connect these (i.e. upstream, or direct attach via 'appliance port') and get your vlan configurations setup to accomidate.

For iSCSI boot example see: http://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-manager/116003-iscsi-ucs-config-00.html

Thanks,

Kirk...

[Hythim Ali El Hadad]

Hi Kirk,

thanks

Actually I see this configuration doc also it is ok for the storage configuration

I'm asking only for what to consider to connect iscsi array to ucs in a very simplest way as it'll be a temp solution for 2 months with no user load.

so is it ok to connect it to nexus7k Ethernet ports and start to configure

or I must get iscsi switch and iscsi cables ..etc

the connections only is my concern and if it'll accept 8 boot Luns for my servers beside the shared data Luns or it isn't doable

thanks again

[Kirk J · Accepted solution]

Greetings.

There is no such thing as an 'iSCSI' specific switch, as it is purely run over ethernet, like NFS, CIFs, etc.

You just need to configure your vlans at the UCSM level as well as the N7K trunk ports to carry the iSCSI based traffic.

You can utilize port-channels between the FIs and the N7K so you have multiple 10Gb ports carrying your traffic, and multiple ports from your N7K to your storage processors.

We normally see people hitting storage processor performance constraints before they run into individual 10Gb link saturation.

If storage performance is a concern you can create a disjoint layer 2 config, and only allow your iSCSI vlans on specific uplinks to the N7k, while utilizing additional uplinks to carry non-iSCSI traffic.

If you are connecting your iSCSI SAN directly to the FIs (using appliance ports), then make sure you have enough Storage Processor ports connected to the FI 'appliance' ports, and with the current vlan configuration.  Your storage processor MFG will determine other requirements such configuring the appliance ports as 'access' or 'trunk' ports, etc.

Kirk...

[Mohammed Kamal MOULINE]

Hello Kirk, 

I have this scenario UCS FI6248 UCSM 3.1, I need to connect a V3700 storage that is connected to a EN4093R 10Gb Ethernet in with 10GB port. 

Questions:

1) if I have to connect the FI to EN4093r have we to configure the uplink port to the native vlan number of the EN4093r port ? any idea what configuration have to be done on the EN4093r side ?

2) if we connect the V3700 port directly to the FI, the port have to be appliance port or uplink port, ?

Any feedback will be very appreciated, 

Kind Regards,

Kamal

[Kirk J]

Greetings.

I'm not familiar with the Lenovo switch you previously mentioned, but assuming it's just a standard layer 2 switch, and handles trunking, then there is no reason  you can't hook your iSCSI san device off of it.

The port config would need to be an uplink trunking port.

I would avoid involving native vlans, and simply trunk/tag the vlan you want to use for your iSCSI traffic.

If you are not short on FI ports, then you would get best performance by using specific uplink ports to only carry iSCSI traffic (called disjoint layer2 config), and you will need to use your vlan manager to only allow the iSCSI vlan on the iSCSI uplinks, and non-iSCSI vlans only on the other uplinks.

If you want to directly connect the iSCSI appliance to the FIs,,, then the ports would be configured as 'appliance' ports.  In appliance port mode, you still generally need to allow the iSCSI vlan traffic to make it between FI-A and FI-B, and allow the iSCSI vlan on uplink ports.  This requirement comes up generally when iSCSI storage controllers fail-over, and an initiator on B side needs to get to controller port on A side.  There are configurations that can be setup to keep initiator and storage traffic switched locally per FI, but kind of outside the scope of what I want to type up in a forum.

Once you have confirmed you have your iSCSI connections correctly established, then you can increase your through put by enabling Jumbo frames.  I've seen jumbo frames increase storage throughput anywhere from 15-40 %.

Thanks,

Kirk...