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Can't attach to new cluster

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BillKOM
Occasional Advisor

Can't attach to new cluster

I'm new to these units and have been making my way via brute force & ignorance.

That being said, I'm having a small issue with a cluster. I have it created with two nodes. When I try to point my initiator at the cluster IP, I get a target error. If I instead try to use the IP of either cluster node, it connects without any problem. I've been reading about the failover manager but I'm not sure if that is the missing piece or not.

What am I doing wrong?
13 REPLIES
Bryan McMullan
Trusted Contributor

Re: Can't attach to new cluster

Are you talking about using the VIP IP as your Gateway? If so, just use a manager or two and you'll be fine (really, just the two IP's of your units). The gateway is only used to list targets and once connected, the VIP should be used correctly (assuming you're using load balancing).

FOM is only needed when you have multiple sites as backup. It shouldn't be necessary with your two units.
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

I'm not sure what a VIP IP (virtual IP?) is, but when I created the cluster, it wanted a IP address for the cluster. My nodes are 10.10.0.123 and .124, with the cluster having a virtual IP of .125. I assumed that you point your initiator to the cluster IP and the nodes handle who responds to it.

Are you saying that I should attach to one of the nodes directly instead? What happens when that node dies, as there is nothing to redirect the request to the other node?

btw thanks for the reply. It's not easy not knowing what you're doing ;)
ajamil786
Frequent Advisor

Re: Can't attach to new cluster

Looks like you the cluster configured and have a VIP. Make sure you have a Server created with under the management group in the CMC with your initiator IQN assigned to this server. Also, any volumes you want this server to attach to should be assigned to the server via the CMC. You do not need to point your initiator to individual nodes if you have "loadbalancing" enabled when you defined the server in the CMC. If you have done the above steps and you still can't connect via VIP than your initiator does not support "iSCSI Redirection". I have seen some HBA's that don't support it. Process is really very simple:

1) Create Management group and cluster
2) Create server and assign initiator iqn
3) Create volume and assign to the server created in step 2.
4) Connect initiator point it to the VIP.
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

Thanks for your reply. I'm using the MS iSCSI Initiator 2.08 for testing before I try to point an ESX server at it. I see some posts online about iSCSI redirection being linked with MPIO. Does that have anything to do with it?
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

I also just found this:

(http://secadmin.wordpress.com/2009/01/16/iscsi-configuration-with-lefthand-and-quorum-management/)

"So at work we decided to go with a Lefthand Implementation of iSCSI, I am rather unhappy to find out that with only 2 units you have to run a virtual machine to complete the Quorum for redundancy."

So now I am confused as to whether or not I need something between the two SANs to act as the quorum. Is this the case? If I have two units in my cluster, do they handle everything themselves with the VIP or is there a missing piece to this puzzle? In the first reply, Bryan said I just need a manager, but not the failover manager. Which manager was he referring to?

Mark...
Honored Contributor
Solution

Re: Can't attach to new cluster

Hi
The way that the P4000 / Lefthand works is that you need to maintain quorum or you will lose access to your volumes if it is lost in the management group.
With a two node cluster then if you lose 1 node quorum will be lost. To get round this you can use a failover manager (FOM) OR a virtual manager (VM).
The FOM is installed under ESX and has no storage capabilities - just a vote really. Therefore in a two node cluster + FOM you have 3 votes. Q = 2. Lose a storage node - no problem Q mainatained by FOM. This is all automatic so volumes stay online.
With the VM you need to create this but you may find that CMC has already created it for you when you created your management group/cluster in the first place. If not just create it.
However DO NOT start the VM! You only start the VM if you lose a node and then if this happens you have to manually start the VM on the surviving node to regain quorum. Note you will lose access to volumes until you start the VM.
When the "failed" node is back/fixed then just stop the VM.
Hopefully that will clear that up for you ?
Mark...
if you have nothing useful to say, say nothing...
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

Thank you so much for your help.

If I want automatic redundancy, it would appear that I do need to run the FOM. I can't have a node go down and then wait for some alert so that I can run to the console and manually activate the VMan. If I install the FOM under ESX and bring it up, do I just scan for it with the CMC? There doesn't seem to be much in the way of options for FOM. Can I assume that the CMC will find the FOM and link it in automagically? Otherwise, I can't see a way to make the FOM aware of the cluster nodes.
Uwe Zessin
Honored Contributor

Re: Can't attach to new cluster

You set up the FOM VM and then use the "find nodes wizard" as if you search for a normal storage node. Then add it to the management group - it will automatically recognized as a FOM.
.
Bryan McMullan
Trusted Contributor

Re: Can't attach to new cluster

I'm sorry about that, I don't know why I was thinking you had three nodes (even though I said 2).

Looks like you're on the right path though.
teledata
Respected Contributor

Re: Can't attach to new cluster

Here's the configuration you would likely run to maintain quorum due to a single node failure:

2 nodes (each running manager plus FoM)
3 nodes (all 3 running manager)
4 nodes (3 out of 4 running manager or 4 managers plus FOM)
5 nodes (all 5 running manager)

So once you have 3 or more nodes you no longer need to run the FOM VM. When LeftHand first introduced this concept you had to buy at least 3 units to have an automated failover cluster, many customers only wanted to start with buying 2 units, so they introduced the virtual FOM VM appliance as a solution.
http://www.tdonline.com
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

Thanks all,

I decided to blow it away and start again now that I have a better grasp on what's going on.

Bryan: No sweat, brother.
Mark...
Honored Contributor

Re: Can't attach to new cluster

Hi,
Install the FOM under ESX and then give it an IP address / mask just like a real piece of h/w or a VSA.
Once powered up just use the CMC to discover it just like a real piece of h/w or a VSA.
Once discovered/found just add in the FOM to your management group - that's it !
Note: Only 1 FOM ***OR*** 1 VM per management group.
Always better to run with an ODD number of managars/FOM config either 3 or 5.
HP recommend that you do not run with more then 5 TOTAL managers even if you have say 20 nodes in a management group.
Mark...
if you have nothing useful to say, say nothing...
BillKOM
Occasional Advisor

Re: Can't attach to new cluster

OK folks, the missing FOM was the entire problem. Now that I've got FOM hooked in, my cluster is performing perfectly.

It might have been handy to have a dialog pop up after you add your second node that the FOM is required for auto-failover if you aren't adding more nodes.

Thank you again everyone for your assistance. When you have so much thrown at you so quickly, you don't have the time to read everyone's 400-page manual. Without a QuickStart guide, this forum was in dispensable in getting me up & running fast.