dedicated switch for vmotion svmotion?

[Thuleman]

I had previously posted some answers to what kind of switch I am currently on here: Cisco switch config for optimal VM performance but I would like to revisit the topic from a different angle.

The switch I am currenly on with 3x Dell PowerEdge 2950 III which all have the Dell LOM card, two onboard NICs and one Intel Quad NIC card each, the EQL PS5000E which has three NICs, and a white-box server which runs OpenFiler on two onboard and a dual Intel NIC.

All that stuff is plugged into the same Cisco WS-C2960G-48TC-L, though the networking folks did distribute the ports across different physical port groups. There is no OOB management, the servers are all on the same public subnet, and they are also on a VLAN (private address space). The VLAN is shared between vMotion and whatever other traffic there is going between servers (i.e. SQL <-> web, etc).

My question is, from a performance standpoint, should I ask for another VLAN to seperate commodity traffic from vMotion traffic? Should I just buy a switch that is dedicated to vMotion and not shared between traffic my servers generate and the traffic other servers on the same Cisco Catalyst switch currently generate?

The networking guys have overall been good to me, but they are overworked and underpaid and I'd rather not bug them with "could we test this out, could we test that out, why don't we try this for a while" etc. I do want to make as close to sure as possible that whatever request I put in next will be what I can stick with for a while. I don't mind buying a switch that would only connect my hardware, otoh I don't want to spend the cash unless it's really necessary.

Thoughts?

 

[calikool]

Ideally you would want the vMotion and svMotion to be on a "management" sub-network. Depends on how fault tolerant you want to be because you would want two physical switches.
1 subnetwork for service console
1 subnetwork for production VMs (the first two could be combined into one vSwitch)
1 subnetwork for vMotion & svMotion using vmkernal


Is NIC Teaming involved? You would think with so many network cards the answer would be absolutely. Use at least two NICs for production and team them. Yes, I would agree that they should be connected to the two switches.

The less physical Nics you have, the more vmport groups you will be running per vSwitch and vLANS you will need. Physical NICS in the ESX meet the sub-network requirements then vLANS are not necessary.

VMWare recommends taking the following actions to minimize networking delays:
Disable port Aggregation Protocol(PAgP) and Link Aggregation Control Protocol (LACP)
Disable Dynamic Trunking Protocol (DTP) or trunk negotiation
Disable Spanning Tree Protocol (STP)

Cisco devices should use PortFast mode for access interfaces or Portfast trunk mode for trunking interfaces.

 

[Thuleman]

So I did make some progress on this, as it turns out the networking folks are happy to provide the Catalyst 2960 but that's it. If I want any switch for my iSCSI traffic then I need to buy one myself. I am considering to do just that. Ideally I'd like to get a router so that I can combine the iSCSI traffic, my private subnet where VMs talk to each other, and provide a VPN for me to connect to my private subnet. Alas it seems that the price for such a Eierlegende Wollmilchsau is just out of my price range.

I am thinking to get a Dell PowerConnect 5424, the 24 ports are overkill of course, but the price is right and it does what it's supposed to do. I'll put the iSCSI traffic on there, my private subnet provided by the networking folks and the normal LAN traffic will continue to go through the Cisco Catalyst.

Any reason to not get that PowerConnect 5424?

 

[calikool]

The Dell looks like a nice manage switch. Hook everything as normal with the redundancy that you need. Then mirror it to the other switch to increase the multipath and room to breath incase of failure on switch 1.

The networking guides van vLAN the ports to their respected groups thus isolating your iSCSI traffic as well.