Administrator Guide

Performance characterization
40 Dell EMC Ready Solution for HPC PixStor Storage | Document ID
./iozone -i0 -I -c -e -w -r 8M -s ${Size}G -t $Threads -+n -+m ./nvme_threadlist
./iozone -i2 -I -c -O -w -r 4k -s ${Size}G -t $Threads -+n -+m ./nvme_threadlist
Figure 22 N to N Random Performance
From the results we can observe that write performance starts at a high value of 6K IOps and rises steadily
up to 1024 threads where it seems reach a plateau with over 5M IOPS if more threads could be used. Read
performance on the other hand starts at 5K IOPSs and increases performance steadily with the number of
threads used (keep in mind that number of threads is doubled for each data point) and reaches the maximum
performance of 7.3M IOPS at 1024 threads without signs of reaching a plateau. Using more threads will
require more than the 16 compute nodes to avoid resources starvation and excessive swapping that can
lower apparent performance, where the NVMe nodes could in fact maintain the performance.
Metadata performance with MDtest using 4 KiB files
Metadata performance was measured with MDtest version 3.3.0, assisted by OpenMPI v4.0.1 to run the
benchmark over the 16 compute nodes. Tests executed varied from single thread up to 512 threads. The
benchmark was used for files only (no directories metadata), getting the number of creates, stats, reads and
removes the solution can handle, and results were contrasted with the Large size solution.
The optional High Demand Metadata Module was used, but with a single ME4024 array, even that the large
configuration and tested in this work was designated to have two ME4024s. The reason for using that
metadata module is that currently these NVMe nodes are used as Storage targets for data only. However, the
nodes could be used to store data and metadata, or even as a flash alternative for the high demand metadata
module, if extreme metadata demands call for it. Those configurations were not tested as part of this work.
Since the same High Demand Metadata module has been used for previous benchmarking of the DellEMC
Ready Solution for HPC PixStor Storage solution, metadata results will be very similar compared to previous
blog results. For that reason, the study with empty files was not done, and instead 4 KiB files were used.