Tag: fio

How to identify NVME drive types and test throughput
By: Date: March 17, 2020 Categories: NVME Performance Tags: ,

Start by identifying the NVME drive type (“nvme list“) since the NVME drives use the nvme protocol, they will not sshow up in the output of lsscsi Identify NVME Identify the nvme drives using “nvme list” nutanix@NTNX-18SM3E420118-A-CVM:10.56.6.36:~/tmp$ sudo nvme list Node SN Model Version Namespace Usage Format FW Rev/dev/nvme0n1 S3HDNX0KC00137 SAMSUNG MZWLL1T6HEHP-00003 1.2 1 1.60…

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Working with fio “distribution /pereto” parameter
By: Date: November 12, 2018 Categories: Nutanix,X-Ray Tags: ,

The fio Pareto parameter allows us to create a workload, which references a very large dataset, but specify a hotspot for the access pattern.  Here’s an example using the same setup as the ILM experiment, but using a Pareto value of 0:8.  My fio file looks like this.. [global] ioengine=libaio direct=1 time_based norandommap random_distribution=pareto:0.8 The…

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The return of misaligned IO
By: Date: May 25, 2017 Categories: Debugging Tags: , ,

We have started seeing misaligned partitions on Linux guests runnning certain HDFS distributions.  How these partitions became mis-aligned is a bit of a mystery, because the only way I know how to do this on Linux is to create a partition using old DOS format like this (using -c=dos  and -u=cylinders) 

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