Problems with NFS Datastores

[notyjoey]

Hey,

I apologize if this is not the right place to ask the question.

I have two host machines both running ESXi. I've configured a cluster which spans these two hosts. Within the cluster configuration I've gone ahead and enabled vSphere HA.

Now, I've created a VM within the cluster and all went well with that. I wanted to setup vmware FT on this machine..

The problem is that when I try to migrate the secondary vm I found that the ESXi hosts are unable to see each others datastores.

The VM is currently on the host I'll call 117. I'm trying to "Migrate Secondary" on to host 115. I get this message.

Unable to access the virtual machine configuration: Unable to access file [datastore_117] test/test_1.vmx

Virtual disk 'Hard disk 1' is not accessible on the host: Unable to access file [datastore_117] test/test.vmdk

[vThinkBeyondVM]

is [datastore_117] datastore shared across both hosts? As per me, its local datastore with host 117. That is the reason you are coming across this issue.

Cluster requirement of FT :

ESX/ESXi hosts have access to the same virtual machine datastores and networks.

Refer:VMware vSphere 4 - ESX and vCenter Server

[notyjoey]

Thanks for the the quick reply. It is not currently shared. [datastore_117] is local to the esxi host 117. I have not been able to figure out how to share it with the 115 machine. I've spent quite a few hours googling and reading but haven't quite been able to figure that part out as of yet. What I did see was to create an NFS datastore but from what I've also read, esxi host doesn't seem to support the NFS server to be able to share that datastore over nfs.

[vThinkBeyondVM]

Here is the way to add your NFS shares across multiple hosts.

VMware vSphere 4 - ESX and vCenter Server

If you use VI client, you need to do the same steps fro both ESXi hosts. If you are using web client, in the same UI workflow, you can share NFS shares with both ESXi host.

[vThinkBeyondVM]

Note that NFS (NAS) storage can be shared across multiple host & vSphere HA & FT does support NFS(NAS) storage.

[notyjoey]

I've tried that but without much luck.

When I go to create that NFS share I use the following values

datastore name:datastore_115_a

Server: my_ip_address

Folder: /vol/datastore_115_a

The error I get from trying to mount it is:

NFS mount my_ip_address:/vol/datastore_115_a failed: Unable to connect to NFS server. 

Sysinfo set operation VSI_MODULE_NODE_mount failed with error status Unable to connect to NFS server

I know that /vol/datastore_115_a does not exist but I get the same error regardless if i point it to /vmfs/volumes/datastore_115 . I've also whitelisted the IPs of the two esxi host machines, on each machine.

Is there maybe a better way to go about getting these datastores shared across multiple servers?

Joe

[vThinkBeyondVM]

The way you are trying is the easiest way.

Can you make sure all the above details are correct? Also refer this KB :http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=102070...

[notyjoey]

Hey,

Thanks again for all the help. I can vmkping both ones from each other.

Just to make sure I understand what the details really mean, I'll put what I think they mean. Please correct me if I am wrong.

datastore name:datastore_115_a (this is the name of the datastore I want to create)

Server: This is the IP Address of the esxi host that has the datastore I want to mount.

Folder: /vol/datastore_115_a ( this is the path where to mount the datastore that is on the machine above)

Did i get it right?

[a_p_]

If I understand your posts correctly you don't have a separate NAS server, and the datastores are local to the ESXi hosts?

In this case you cannot share the datastores.

André

[notyjoey]

Hey André,

You are right. I don't have any separated NAS servers. Based on this, I cannot have the 115 machine being able to access the local datastores on 117, and the same for 117 machine accessing the datastores on 115?

[a_p_]

Exactly, ESXi doesn't provide an option to share local datastores. If you want to share data you either need to have an external storage system, or you can create a NAS or iSCSI server as a virtual machine on one of the ESXi hosts.

André

[notyjoey]

Ah I see.

So, If I wanted to take advantage of HA/FT, given that I have two servers without a NAS, what would the best way to go about it be?

From what I've gathered, maybe this sort of configuration:

1) A VM per host using a large amount of the local datastore storage space. I create a NFS share to mount via both esxi host machines.

2) Go through the above process and create the new datastores. Which should leave me with the new shared data stores which can house the primary/secondary vmdk files.

Sounds easy enough I think if it is true.

[a_p_]

The steps you mentioned are basically ok, but in order to test HA and FT it would be best to have a third/independent system for the storage. Think of it!, You want to test high availability, which requires that you simulate host failures. If the hosts however provide the storage for themselves you will be limited in testing, i.e. you can only shut down the ESXi host which does not currently host the storage VM.

André

[notyjoey]

Ah I see. I was thinking more of a 1:1 mirror configuration of one another. So let me ask you then, with FT/HA and a dedicated storage machine, would the hosts still be running the VMs on local storage with the secondary being ran from the shared datastore?

[a_p_]

In order for HA to work, both hosts need to have access to the same datastore. The VM itself only exists once on the shared datastore, and when the host - on which the VM is currently running - fails, the same VM is restarted on the other host.

André

[notyjoey]

Ah I see. Allow me to ask what may be a dumb question. What is the point of the "Migrate Secondary" ioption under "Fault Tolerance" if both hosts have access to the same vmdk file?

[notyjoey]

Ah I think I may have figured that out. It's where you want to migrate the VM to but no the actual VM vmdk files.

[a_p_]