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Dell HPC NFS Storage Solution - High Availability (NSS-HA) Configuration with Dell PowerVault
MD3260/MD3060e Storage Arrays
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A.2. mdtest
You can download mdtest from http://sourceforge.net/projects/mdtest/. Version 1.8.3 was used in
these tests. It was compiled and installed on a NFS share that was accessible by compute nodes.
mdtest is launched with mpirun. For these tests, OpenMPI version 1.4.3 was used. The following table
describes the mdtest command-line arguments.
mpirun ARGUMENT
DESCRIPTION
-np
Number of Processes.
--nolocal
Instructs mpirun not to run locally.
--hostfile
Tells mpirun where the hostfile is located.
mdtest ARGUMENT
DESCRIPTION
-d
The directory mdtest should run in.
-i
The number of iterations the test will run.
-b
Branching factor of directory structure.
-z
Depth of the directory structure.
-L
Files only at leaf level of tree.
-I
Number of files per directory tree.
-y
Sync the file after writing.
-u
Unique working directory for each task.
-C
Create files and directories.
-R
Randomly stat files.
-T
Only stat files and directories.
-r
Remove files and directories left over from run.
As with the IOzone random access patterns, the following procedure was followed to minimize cache
effects during the metadata testing:
 Unmount NFS share on clients.
 Stop the cluster service on the server. This unmounts the XFS file system on the server.