NFS Datastore cannot be connected after a restart

[wings7351]

Hi, maybe someone can give me a hint of why this is happening. I am using ESXiU3, a NexentaStor is used to provide a NFS datastore. For other reason I had to restart the ESXi server. When it came back, I can no longer connect to the NFS datastore. I changed nothing. Is it possible the ESXi server NFS client service stopped? I can vmkping to the NFS server. When I deleted the original NFS datastore and try to remount the NFS resource, I got error message: unable to mount; unable to connect to NFS server. But I did not touch the NFS server at all.

Anyone can give me a hint? Thanks.

[runclear]

is your DNS server a VM? ie: did you connect your NFS server using DNS names? Maybe esx cannot resolve the netbios name? ... (i only ask this b/c ive personally done it on a test system of mine lol.

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[javelin]

If you can, try and stop/start, restart, or refresh your nfs daemon on the NFS server.

I had the same issue and once I've refreshed the nfs daemon, the NFS share directories

became available immediately.

Hope that helps.

jav

[wings7351]

thank you for your suggestions.

Runclear, I did not use DNS, I used ip address.

Javelin, I will try it. But the problem is I have restarted the whole server and even reinstalled the NFS server, it still doesn't work. What I don't understand is that they work together without problem before the ESXi server was restarted.

Bo

[BrendonR]

I just had the same problem.

I am using Solaris X86 as my NFS host. It was configured to use the DNS server which is a VM on the NFS share which was down. However, my ESXi box was configured to refer to the NFS share by IP address not host name.

I edited /etc/resolv.conf on my Solaris host and added an internet DNS server and immediately the NFS share showed up on the ESXi box.

So this leads me to believe that NFS on the Solaris host won't actually share until it can contact a DNS server. So in my instance its on the NFS host side rather than the NFS client side (ESXi)

Hope that helps.

[wings7351]

In my case though, I have never used DNS for this purpose. I've always used IP address.

[Chamon]

Can you check to see that your Netstore does not think that the ESXi host still has the share mounted? If it does then it may not let the same machine mount it twice.

Does it show as mounted on the ESXi host with

df

? I don't know if that command works on ESXi. But if it thinks it still has the mount but really doesn't that could also be an issue. I had a similar problem but can't remember witch end it was on, NFS or ESX.

[BrendonR]

I understand you are using IP addresses and not host names, thats what I am doing too.

However, is your NexentaStor configured to use a DNS server which is unavailable because its located on a NFS datastore?

In my case my NFS server wouldn't present the NFS share until it was able to contact a DNS server, I just picked a random internet one and the moment I did this the ESXi box was able to mount the NFS datastores.

So its not a name resolution issue but, in my case, a dependancy on the NFS server to be able to contact a DNS server.

[shechtl]

I still had the same problem with our open-e DSS NFs storage.

See my post here. http://communities.vmware.com/thread/208423

I have only a ugly solution for this problem.

open-e tries to make a bugfix in their NFS server to fix this problem. I tried it with freeNAS and that worked for test.

[TechFreakZ]

Hi shechtl,

I have just had exactly the same problem! So frustrating.

I also, for once, appear to be able to offer a solution!

I copied one of our linux based DNS servers & our NATing router VMs off the SAN and on to the storage local to the ESXi server. This DNS server can also forward requests to the internet through the NATing router.

I configured Open-E DSS to use this DNS server and the OPENDNS servers available on the internet. I figured at least one of them would work.

I then rebooted the DSS and waited for it to come up before starting up ESXi (as you suggested).

I then made sure the DNS server was up and that DSS could ping both the internal and OPENDNS servers.

I then tried for the millionth time to re-add my old NFS share in to ESXi and bingo, it works. At last!

There is a note in the NFS share section on DSS that says the following "If the host has an entry in the DNS field but does not have a reverse DNS entry, the connection to NFS will fail."

So it looks like even if you don't need DNS to resolve the IP, NFS does some reverse lookup and gets upset if it can't find any matches or at least a reply from a DNS server. Which is kind of useless if your DNS server is located in the VMs that are stored on the NFS server. I feel another "chicken and egg" moment coming on!

I'm considering installing a tiny linux OS with a DNS server configured with no zones and setting this to start before all the other VM's. DSS will ask for the name to match the IP, will fail, but may still allow ESXi to connect and run the other machines a short while afterwards?....

I hope this helps someone else out there.

If you need any more detail, just shout.

Cheers

TFZ

[harryc]

From the NFS server:

could you post your /etc/dfs/dfstab - are there hostnames in there ?

How about in /etc/hosts.allow or /etc/hosts.deny ?

[TechFreakZ]

Hello harryc,

Unfortunately I do not believe I have access to the /etc/dfs/dfsta , /etc/hosts.allow or /etc/hosts.deny files on Open-E DSS v6.

Can anyone suggest how to access these files?

Best regards

TFZ

[NTShad0w]

hi all,

old topic but problem still actual, any solution for NexentaStor v4.0.4 requirements to see actual running DNS to serve NFS DS connected by IP (not by name)...?

Thanks