White Papers

Dell HPC NFS Storage Solution - High Availability (NSS5.5-HA) Configuration with Dell PowerVault
MD3460 and MD3060e Storage Arrays
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5. NSS5.5-HA I/O Performance
This section presents the results of the I/O performance tests for the current NSS-HA solution. All
performance tests were conducted in a failure-free scenario to measure the maximum capability of the
solution. The tests focused on two types of I/O patterns: large sequential reads and writes, and small
random reads and writes.
A 360TB configuration was benchmarked with IPoIB cluster network connectivity. The 64-node compute
cluster described in section 4.2 was used to generate workload for the benchmarking tests. Each test
was run over a range of clients to test the scalability of the solution.
The IOzone and mdtest utilities were used in this study. IOzone was used for the sequential and
random tests. For sequential tests, a request size of 1024KiB was used. The total amount of data
transferred was 256GiB to ensure that the NFS server cache was saturated. Random tests used a 4KiB
request size and each client read and wrote a 4GiB file. Refer to Appendix A for the complete
commands used in the tests.
5.1. IPoIB sequential writes and reads
In the sequential write and read tests, the I/O access patterns are N-to-N, i.e., each client reads and
writes to its own file. Iozone was executed in clustered mode and one thread was launched on each
compute node. As the total transferred data size was kept constant at 256 GiB, the file size per client
varied accordingly for each test case. For example, 256 GiB file was read or written in 1-client test
case, 128 GiB file was read or written per client node in 2-client test case.
Figure 3 shows the sequential write and read performance. The figure shows the aggregate throughput
that can be achieved when a number of clients are simultaneously writing or reading from the storage
over the InfiniBand fabric.
Leveraging the new PowerVault MD3460 storage array, significant I/O performance improvements were
observed during our tests:
 The peak read performance is up to 5.48 GB/sec, which was more than 20% improvement as
compared to the peak number of NSS5.0-HA (4.28 GB/sec).
 The peak write performance is up to 2.25 GB/sec, which gains more than 50% improvement as
compared to the peak number of NSS5.0-HA (1.32 GB/sec).