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Dell HPC NFS Storage Solution High Availability (NSS-HA) Configurations with Dell PowerEdge 12th
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A.2. mdtest
You can download mdtest can be downloaded 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. dtest is launched with mpirun. For these tests, MPICH2 version 1.3.2 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
 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 umounts the XFS file system on the server.