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Dell HPC NFS Storage Solution High Availability Configurations with Large Capacities
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As with the IOzone random access patterns, the following procedure was followed to minimize cache
effects during the metadata testing:
o Unmount NFS share on clients.
o Stop the cluster service on the server. This umounts the XFS file system on the server.
o Start the cluster service on the server.
o Mount NFS Share on clients.
Metadata file and directory creation test:
# mpirun -np 32 --nolocal --hostfile ./hosts /nfs/share/mdtest -d
/nfs/share/filedir -i 6 -b 320 -z 1 -L -I 3000 -y -u -t -C
Metadata file and directory stat test:
# mpirun -np 32 --nolocal --hostfile ./hosts /nfs/share/mdtest -d
/nfs/share/filedir -i 6 -b 320 -z 1 -L -I 3000 -y -u -t -R -T
Metadata file and directory removal test:
# mpirun -np 32 --nolocal --hostfile ./hosts /nfs/share/mdtest -d
/nfs/share/filedir -i 6 -b 320 -z 1 -L -I 3000 -y -u -t -r
B.3. Checkstream
The checkstream utility is available at http://sourceforge.net/projects/checkstream/. Version 1.0
was installed and compiled on the NFS servers and used for these tests.
First, a large file was created using the genstream utility. This file was copied to and from the NFS
share by a client using dd to mimic write and read operations. Failures were simulated during the file
copy process and the NFS service was failed over from one server to another. The resultant output files
were checked using the checkstream utility to test for data correctness and ensure that there was no
data corruption.
Given below is sample output of a successful test with no data corruption.
checkstream[genstream.file.100G]: ------------------------------------------------
checkstream[genstream.file.100G]: valid data for 107374182400 bytes at offset 0
checkstream[genstream.file.100G]: ------------------------------------------------
checkstream[genstream.file.100G]: end of file summary
checkstream[genstream.file.100G]: [valid data] 1 valid extents in 261.205032
seconds (0.00382841 err/sec)
checkstream[genstream.file.100G]: [valid data] 107374182400/107374182400 bytes (100
GiB/100 GiB)
checkstream[genstream.file.100G]: read 26214400 blocks 107374182400 bytes in
261.205032 seconds (401438 KiB/sec), no errors