Unable to change ownership of NFS mount

I am unable to change the ownership of a filesystem which an NFS mount. There is no error on the screen or in the logs.

# chown app_user /data/mountpoint
# ls -ld /data/mountpoint
drwxrwxr-x 6 nobody app_group 8192 Apr 25  2015 /data/mountpoint

The volume has been mounted with NFS4.

# mount | grep mountpoint
NAS_Server:/vol/example on /data/mountpoint type nfs (rw,nolock,vers=4,addr=IP_ADDR,clientaddr=IP_ADDR)

The NFS client in RHEL 6 defaults to NFS4 if the server supports it. If not, it will fall back to NFS3. As this is not meant to be an NFS4 mount, I remount the volume with NFS3. Continue reading

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df does not show all NFS mounts in RHEL 7.1

This is due to a bug in coreutils. It is fixed in coreutils-8.22-12.el7_1.2. df is a part of coreutils package.

# rpm -qf `which df`
coreutils-8.22-11.el7.x86_64

As a workaround, use

    #  df -t nfs -a

    #  grep nfs /etc/mtab

    #  cat /proc/mounts | grep nfs

The lack of jumbo frames burns our world down

NAS Datastores are greyed out in ESXi hosts. VMs becomes inaccessible, lots of them. One host in the cluster was rebooted and everything looks fine except we can see what’s in the datastores. NFS MaxQueueDepth is set to 64 pretty much in all hosts. This cluster has it set to the Max value

~# esxcfg-advcfg -g /NFS/MaxQueueDepth
Value of MaxQueueDepth is 4294967295

We change it to the recommended value of 64 and rebooted the host. We are still stuck. Then came our savior. After hours of troubleshooting, it takes NetApp senior support engineer to ask us “Is Jumbo frame working”?
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A good part of today was spent on understanding the order of filesystem mounting in RHEL6

I have been living under the assumption that in Linux, filesystems are mounted solely based on the order in /etc/fstab. This is true only as long as they are the same filesystem type- local or network. I spent a good deal of time today revisiting the boot process and understanding the order of mounting in RHEL 6. And this post applies to RHEL 6 because I can’t say for sure for other distro or other RHELx without a close look but I am guessing it should be close to similar for pre-RHEL6 versions.

The Problem
User wants to mount an NFS volume with a dependency on local lv. Thinking the order is what matters in fstab, I place it like this in fstab and reboot.
Continue reading