I apologize in advance if this question has been asked a thousand times before but I'm just starting to get my feet wet with vlans and everything is still pretty abstract to me and I'm not sure if the answers from the other thread is applicable to what I am trying to do. I'm trying to create an iscsi vlan that spans two switches, I'm thinking about getting a couple of 5424s for this. This is how I am envisioning it:
A couple of questions first, in the setup above, if I connect both port 1 to my main switch, ports 2-12 will become part of the local main network right? Ports 13-20 will be it's own lan and will not receive broadcasts from the main network? Are four ports enough / too-few / too-much for interconnect between the two switches?
I have read this helpful page, but I am not sure how to implement the vlan with the instructions provided, I think the vlan setup is just another procedure on top of of the setup shown in that page.
Although I still don't understand most of how vlans work, I feel I'm getting close to what I am trying to do, could someone help me understand this a bit more?
So after a couple of days without a reply I'm starting to think that what I'm trying to do is not possible, am I going about this the wrong way? If so, then what would be the best way to use a couple of 5424s to switch iSCSI traffic on some ports and make the rest part of our main LAN?
Call-in, did you ever get this setup to work? I'm tasked with setting up something similar in my environment for use with a NetApp filer, but I'm having trouble finding guidance on the configuration.
I have two 5424 switches that I'm going to use as my SAN. Originally, we thought we were going to be purchasing an Equillogic PS6100, so we set these up as pure iSCSI switches with a LAG and didn't even bother with a port for web-based config. In the end, our applications dictated that we needed a filer that supported multiple protocols, so we went with the NetApp 2240-2. Now, I have to reconfigure these switches to support both iSCSI and NFS traffic, I'm assuming on seperate VLANs with both VLANs utilizing the LAG. I initially thought about using all ports to do either iSCSI or NFS depending on the VMs on a given host, but I can't find any config examples like that. I have networking experience, but I definately feel like I'm in over my head on this one, so any advice is welcome. Here is a picture of what I assume the end result should be:
And here is the current config from back when we were looking to do pure iSCSI:
spanning-tree mode rstp interface port-channel 1 spanning-tree portfast exit interface range ethernet all spanning-tree portfast exit interface port-channel 1 flowcontrol on exit interface range ethernet all flowcontrol on exit port jumbo-frame vlan database vlan 100 exit interface range ethernet g(1-20) switchport access vlan 100 exit interface port-channel 1 switchport access vlan 100 exit interface vlan 100 name "SAN VLAN" exit interface range ethernet g(21-24) channel-group 1 mode on exit iscsi target port 9876 address 0.0.0.0 iscsi target port 20002 address 0.0.0.0 iscsi target port 20003 address 0.0.0.0 iscsi target port 25555 address 0.0.0.0 no iscsi enable hostname SAN2
I have seen the article that you refer to linked many times in this forum, and its quite helpful. Also, your post does a good job of describing how to configure the picture I sent. There is another alternative though that might be more appealing to us, and I can't find any instructions on how to achieve it here. See, the inherent problem with the picture I sent is that your VM hosts would each have to have 2 ports for NFS traffic and 2 ports for iSCSI traffic (2 protocols across 2 switches), but what if I only have 2 ports available per host for the SAN? Is it possible to to group up the first 18 ports into 2 VLANs such that you have a VLAN for NFS **AND** a VLAN for iSCSI on a given port? The traffic would still be segregated and could have different configuration options, and I would need only 2 physical NICs for SAN per host. If this is possible, how would I accomplish it, and wouldn't I have to optimize iSCSI in this scenario? See the picture...
Also, feel free to talk me out of doing it this way if you foresee me having problems...
I would look at the config on the document above and mold that to the ISCI ports. You would need port jumbo frame, flowcontrol on spanning tree portfast on the ISCI ports. Then configure the LAG choose Static of Dynamic (LACP).
Creating LAGs – Static Two-port LAG
console> enable
console# configure
console(config)# interface range ethernet g1-2 (adjust for the 4 ports bonding the SAN switches together)
console(config-if)# channel-group 1 mode on
console(config-if)# exit
console(config)#
Creating LAGs – Dynamic LACP LAG
console> enable
console# configure
console(config)# interface range ethernet g1-2
console(config-if)# channel-group 1 mode auto
console(config-if)# exit
console(config)#
On the LAG port-channel or uplinks you will need to create a trunk/general switchport. This will allow multiple VLANs to traverse back and forth between the switches. Depending on the compatibility of your devices you will use trunk or general.
console(config-if)# name ISCI Traffic (Optional Naming)
console(config)# interface vlan 3
console(config-if)# name NFS Traffic
Then any ports that you want to connect to VLAN 2 would need this configuration. You can use the range command for multiple ports. Then a similar set up for the ports in VLAN 3.
Here is the config that I've come up with for the first option, with NFS and iSCSI relegated to separate physical ports on the switches. Remember that in this config, port 19 will remain on VLAN 1 for management. I'm 99% sure of all of this setup with the exception of creating the trunking LAG and enabling portfast/rstp on it. Please advise...
no iscsi enable no iscsi target port 860 no iscsi target port 3260 no iscsi target port 9876 no iscsi target port 20002 no iscsi target port 20003 no iscsi target port 25555
DO SOME GLOBAL LEVEL CONFIGURATION
spanning-tree mode rstp port jumbo-frame
CONFIGURE ETH PORTS
interface range ethernet all spanning-tree portfast speed 1000 duplex full flowcontrol on no port storm-control broadcast enable exit
You would not enable portfast on the LAG Trunk, that should be with the access mode commands along with flowcontrol.
console(config)# interface range ethernet g(11-18)
console(config-if)# switchport mode access
console(config-if)# switchport access vlan 200
console(config-if)# spanning-tree portfast
console(config-if)# flowcontrol on
On the 4 port LAG do not use any spanning tree commands.
If your vlan traffic is needing to reach to the core you will need trunk/general settings on that port also where VLAN 2 is.
Additional info:
8 Unicast Storm Control
A traffic “storm” occurs when a large outpouring of packets creates excessive network traffic that degrades network performance. Many switches have traffic storm control features that prevent ports from being disrupted by broadcast, multicast, or unicast traffic storms on physical interfaces. These features typically work by discarding network packets when the traffic on an interface reaches a percentage of the overall load (usually 80 percent, by default).
Because iSCSI traffic is unicast traffic and can typically utilize the entire link, it is recommended that you disable unicast storm control on switches that handle iSCSI traffic. However, the use of broadcast and multicast storm control is encouraged.
The following example for Dell PowerConnect 5400 series switch cover disabling Unicast Storm Control on the user specified interfaces responsible for passing iSCSI traffic. They begin assuming the user is in privileged EXEC mode, and disable unicast storm control on local switch port 1.
Dell PowerConnect 5400 Series CLI Example:
# configure
# interface ethernet g1
# no port storm-control include-multicast
# end
Answering you 2nd scenario:
If you have a virtual switch on your VM host you may be able to set up trunk/general mode on both sides where multiple vlans can traverse. The packets need to be tagged at some point and that is where it gets tricky. The switchport access mode is what tags traffic for a certain VLAN. There is not much documentation on this. That said the setup we have laid out above is the more utilized and recommend option for isolating traffic into different VLANs.
Willy, you are the best! It would have taken me MUCH longer to get responses like this from Cisco (I know from experience). I am kind of bummed that I need to buy more NICs, but I can live with it if it means stuff will just work.
Concerning VLAN 2, I see your point. The purpose of that port will be to replicate data between remote SANs over a 10Mb connection linked to our core switches. I don't yet know what protocol that replication traffic will require, but lets assume that its just accessing the volumes as NFS shares. In that case, are you saying I would have to create a trunk between the core switches and the SAN switches and allow only VLAN 100 over that trunk?
I will try out these suggestions and reply here with any questions/problems...
call-in
4 Posts
1573
0
Posted December 16th, 2010 11:00
So after a couple of days without a reply I'm starting to think that what I'm trying to do is not possible, am I going about this the wrong way? If so, then what would be the best way to use a couple of 5424s to switch iSCSI traffic on some ports and make the rest part of our main LAN?
Anybody?