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Improving NFS Performance on HPC Clusters with Dell Fluid Cache for DAS
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IOzone Argument
Description
-t
Number of threads
+m
Location of clients to run IOzone on when in clustered
mode
-w
Does not unlink (delete) temporary file
-I
Use O_DIRECT, bypass client cache
-O
Give results in ops/sec.
For the sequential tests, file size was varied along with the number of clients such that the total
amount of data written was 256G (number of clients * file size per client = 256G).
IOzone Sequential Writes
# /usr/sbin/iozone -i 0 -c –e –w –r 1024k –s 4g –t 64 -+n -+m ./clientlist
IOzone Sequential Reads
# /usr/sbin/iozone -i 1 -c -e -w -r 1024k -s 4g -t 64 -+n -+m ./clientlist
For the random tests, each client read or wrote a 4G file. The record size used for the random tests
was 4k to simulate small random data accesses.
IOzone IOPs Random Access (Reads and Writes)
# /usr/sbin/iozone -i 2 -w -r 4k -I -O -w -+n -s 4G -t 1 -+m ./clientlist
By using -c and -e in the test, IOzone provides a more realistic view of what a typical application is
doing. The O_Direct command line parameter allows us to bypass the cache on the compute node on
which we are running the IOzone thread.