Did you try to share /mnt/md0?

eg: /etc/exports
Also I'm wondering about this log line from the server:
That means in server POV, there is no /mnt/md0/data ....

But there is absolutely a /mnt/md0/data directory. I have lots of files in there. I wonder if it's trying to share that folder before MDADM can initialize the array? (grasping at straws)

And if I share /mnt/md0, will this not share the ENTIRE array? (I'll give it a shot though later on..... this machine also doubles as my Plex server and a few people are on there right now so I'll muck with it later.)

Hi again road_hazard,

OK thx for the info. Since you're able to share other subdirectories with Samba, it should be possible with nfs.

Your mdadm.conf has a line in there that says CREATE should use 0660 permissions. If a directory doesn't at least give execute permission to "everyone" (ex. 0661), even listing contents of a directory won't work.

Since information from an earlier post of yours confirms the permissions on /mnt/md0/data are 0777, you could perhaps verify that the permissions for the "everyone" category of the parent directories (/mnt and /mnt/md0) are at least at "execute" level (ex. 0771 0751).

Cheers.

Hi road_hazard,

Sorry - meant to suggest one more thing ... :

These are the options I use on my own server for nfs exports:

I notice some of these aren't included in your exports file statements, particularly the "nohide" and "no_subtree_check" options.

Perhaps you could try experiment with adding those.

Cheers.

Hello, yes it will share /mnt/md0, the whole array...
It's just for testing, if it succeeds then the raid array is not the issue.

Within the array, I have about 10 folders shared out via Samba. Will that cause any problems?

No, it should be fine. NFS and Samba shouldn't interfere with each other

edit, don't write a potential opened file by another host, just see if you can browse content

Another step in the right direction! When sharing out /mnt/md0, I was able to browse all the folders from a client machine! Even the data directory! But now, what the flip is so wrong with that /data dir that when sharing just it, no go?!?

Maybe it doesn't like the directory name?
Seriously, at this point I would rename the directory and retry to share it in /etc/exports

Also try the -r option when invoking exportfs
edit: you don't need to reboot after /etc/exports changes, just do

Another monkey wrench...... tried a few different directories on /mnt/md0 and nothing worked. I can share out the ENTIRE array or nothing on it. No middle ground apparently.

... have you tried experimenting with options I mentioned in my previous post ?

Cheers !

Something not yet investigated is how you attempt to mount data on client
eg:

Not yet. I'm going to add some extra drives to my Antergos box and setup a MDADM array on it and test your theory there first then try it on the server in question. Not that I don't trust your expertise or anything but if I wreck my RAID 6 array, I'd be a really, REALLY sad panda.

This one: mount -t nfs server:/mnt/md0/data /mnt/clientmountpoint

It's just weird that if I share /mnt/md0, that works. But sharing /mnt/md0/data, /mnt/md0/test, /mnt/md0/Pictures, /mnt/md0/incoming ...... all those fail. Wonder if I should open up a bug report somewhere. But with who? Is this an MDADM problem? NFS-server? NFS client?

Do you (or anyone reading this thread) have an MDADM array setup to test things on your side? Maybe this is a Mint specific failure? (Or, user error. )

:-) .. I hear ya and completely understand.

In answer to your question in a subsequent post, my own server, to which I was referring, is set up with mdadm (RAID5) with LVM on top. In my particular case, I have shared an entire subdirectory tree under the /home directory (i.e.: /home/[shared directory tree]). The way I have set it up is to share the entire [shared directory tree] under /home, as well as each of the next level subdirectories under that, separately. This gives me the granularity I require and I manage permissions for the different users the usual way. Similarly to your case, I also use Samba sharing for Windows clients.

I don't believe your issue has to do with your RAID (mdadm) setup. The fact that you're able to use the directories normally on the server itself and the fact that your Samba sharing works leads me to believe it is more of an nfs-specific issue or a permissions issue.

Let us know when you've had a chance to experiment with my previous suggestions.

Cheers !