Administrator Guide

Performance characterization
31 Dell EMC Ready Solution for HPC PixStor Storage | Document ID
Figure 16 N to 1 Sequential Performance
From the results we can observe again that the extra drives benefit read and write performance. Performance
rises again very fast with the number of clients used and then reaches a plateau that is fairly stable for reads
and writes all the way to the maximum number of threads used on this test. Notice that the maximum read
performance was 24.8 GB/s at 16 threads and the bottleneck was the InfiniBand EDR interface, with ME4
arrays still had some extra performance available. From that point, read performance decreased from that
value until reaching the plateau at around 23.8 GB/s. Similarly, notice that the maximum write performance of
19.3 was reached at 8 threads and reach a plateau.
Random small blocks IOzone Performance N clients to N files
Random N clients to N files performance was measured with FIO version 3.7 instead of the traditional Iozone.
The intention, as listed in the previous blog, was of take advantage of a larger Queue Depth to investigate the
maximum possible performance that ME4084 arrays can deliver (previous tests for different ME4 solutions
showed the ME4084 arrays need more IO pressure that Iozone can deliver to reach their random IO limits).
Tests executed varied from single thread up to 512 threads since there was not enough client-cores for 1024
threads. Each thread was using a different file and the threads were assigned round robin on the client nodes.
This benchmark tests used 4 KiB blocks for emulating small blocks traffic and using a queue depth of 16.
Results from the large size solution and the capacity expansion are compared.
Caching effects were again minimized by setting the GPFS page pool tunable to 16GiB and using files two
times that size. The first performance test section has a more complete explanation about why this is effective
on GPFS.
./iozone -i0 -c -e -w -r 8M -s 32G -t $Threads -+n -+m ./threadlist
./iozone -i2 -c -O -w -r 4K -s 32G -t $Threads -+n -+m ./threadlist