iSCSI without fabric

[spseabra]

Hi Guys,

This is probably a stupid question but is it possible to connect an ESX box directly with a network cable to an iSCSI target?

I presently don't have access to a gigabit switch. I was wondering if it's possible to connect directly to the iSCSI box or if it's mandatory to have a console port group on the vmkernel (iSCSI) vswitch and have it go through a physical switch?

tks in advance

[dmorgan]

Never tried it, but in theory you could use a crossover cable... not sure if that would work or not, but fairly cheap and easy to test.

Don

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[ctfoster]

It'll work fine for testing purposes. You wont need a xover - the gigabit ports are normally autosensing.

[mike_laspina · Accepted solution]

Hello,

Yes, you can do that with a cross over cable and you will need to define an iscsi vmkernel, console and target on that same ip subnet and nic.

e.g.

iscsi initiator = 10.0.0.1

extra iscsi console = 10.0.0.2

iscsi target = 10.0.0.3

[spseabra]

Thanks for all the help guys. I've added the extra console IP to the vswitch and that did the trick. Still, could somenone explain to me why this is needed? I really don't understand the theory behind this. I could vmkping the storage without the extra console IP before, shouldn't that be enough?

tkx

[pisko]

hi all

SC is for Send Targets and authentications to you really need it

NFS doesnt need it

br

[spseabra]

Hi pisko,

Tks for the reply. Actually I'm not using any kind of authentication (chap is disabled).

Can you explain why send targets needs the service console IP. I was under the impression that this was only needed if the SC was in a diferent IP subnet...

tkx

[mike_laspina]

Hello,

The console is actually a management interface backplane to the storage devices (and other things). The system needs to monitor the storage devices and act in the event of failure or to query the storage etc. Those functions and many more go throught this interface. It must be available and validated.

Hope that helps.

[spseabra]

Hi Mike,

It's very helpfull indeed. So in order for the iSCSI storage interface to work, it needs it's own subset of service console funtions... Hmm, is this always independent from the main SC and therefore mandatory or is it only needed if the main SC is in a diferent subnet from the iSCSI target?

tks

[mike_laspina]

The iSCSI requirement specs state the where the iSCSI vmkernel network lies then a management console must be able to reach it. While I have not setup a completely routed managment network the theory is that you can define a default gateway on the management plane and vmkernel ports to handle the network reach ability but this creates a lot of complexity. And complexity is not your friend when something goes wrong. Thus it is possible to have one main console but it is much simpler to define an additional one.

Routing can also have a performance drawback that also makes it unappealing.