iSCSI SAN live production network upgrade (Dell MD3000i + PowerConnect & ESXi 4)

[AlbertWT]

Hi All,

At the moment, I've got a direct connection of iSCSI SAN from my Dell MD3000i into the 2x ESXi 4 host with no switch in between, all of the VM is inside the SAN and running on both hosts.

If I'd like to put a switch in between and add one more iSCSI SAN so that both SAN can be accessed / shared with the total of 3 ESXi 4 hosts, how shall I approach this ?

any idea or guideline would be greatly appreciated.

Do I have to schedule down time or can I change the old IP on the existing iSCSI SAN cable manually one by one without damaging/corrupting the VM operation on existing SAN ? or do I have to shutdown the VM and then end the iSCSI connection session manually then reboot the SAN host ?

Thanks,

AWT

[J1mbo]

I would definitely suggest a good downtime window and a carefully designed test strategy to provide the system can withstand switch failure - this is a very fundamental change to your design. Also worth considering (and testing) UPS shutdown orders if you don't have a generator and indeed the split of AC power from different UPS's in case one goes bad.

Also SAN side switches may or may not need multi-port LAG depending on the MD3000's requirements.

http://blog.peacon.co.uk

Please award points to any useful answer.

[AlbertWT]

yes, i want to simplify things without using VLAN so all will be using one new subnet instead of one subnet per cable per port.

i wonder if this is possible to do the iSCSI cable IP subnet change on the fly gradually ?

Kind Regards,

AWT

[JohnADCO]

I have to power cycle the MD3000i anytime I even sneez at and of the NIC interfaces. Pretty sure you will have to power cycle...

Two subnets is the standard with the MD3000i.

[AlbertWT]

thanks for your reply John, the diagram is what i want to achieve.

why 2 subnets ? i was hoping that one single subnet for all iSCSI SAN would be sufficient, plus I also plan to connect additional cable from my vcenter into the iSCSI switch for direct SAN based backup using vstorage API if this is possible ?

do you mean controller 1 SAN 1 should use subnet #1 and controller 2 SAN 2 should use subnet #2 ?

[AlbertWT]

yes John, it is what I want to achieve, why do i have to create

[JohnADCO · Accepted solution]

Standard setup on the MD3000i is for one iSCSI port on each controller to be on one subnet and the other on each controller to be on another.

There have been people successfully running it on one subnet, there have been reports of issues too. I wish we were further along on our Vsphere upgrade, I'm not at a point yet where I can test things like Vmotion.

[AlbertWT]

Thank you John for your suggestion,

I know that with MD3000i there are dual controller (SPo an SP1) with two Ethernet ports on each (total 4 cables go in/out from this unit) but cmiiw, only one controller can operate at the same time while the other is just a failover / standby. From the active SP, two can work simultaneously for two different iSCSI session into the LUNs hosted inside the SAN.

at the moment four cable is running with each own subnet.

so at least in the configuration I shall create two subnet for each SAN.

Kind Regards,

AWT

Message was edited by: AlbertWT