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NFS Mount Options

Question asked by mandoskippy on Mar 8, 2015
Latest reply on Mar 9, 2015 by Ted Dunning
In the documentation for NFS mounting (located: http://doc.mapr.com/display/MapR/Accessing+Data+with+NFS#AccessingDatawithNFS-MountingNFSonaLinuxClient)

The command for mounting the maprfs cluster is:

sudo mount -o hard,nolock usa-node01:/mapr /mapr

The options specified are specific but I wonder are they required for MapR or does something with MapR force us to use those options, or are they just the options that MapR documented.  Specifically:

hard: This forces a hard mount. This can interesting in that applications using the nfs share will continue trying forever on the share, even to the point where kill -9/non-cold reboot won't kill the process.  a soft lock causes the app to get an error if the share is unavailable. Obviously there are pluses and minuses to both, however, I am curious if maprfs REQUIREs a hard mount or if it's just what was documented.

nolock:  This is interesting.  From what I can tell, this disables the abiliy to create file locks.  On a shared, clustered filesystem, this seems like it would actually be a good thing.  Consider apps that may be scaled out on a cluster using the same data directory, perhaps you want to set it up so that an app, when running creates a lock in the data directory so that another instance can use/modify data in that directory.   Will this work? Is there a reason that it specifically documented to use nolock?

Thanks in advance!

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