Add fio

https://github.com/axboe/fio

Author: mincong-h

cluster/disk.md

@@ -1,5 +1,18 @@
 # Disk
 
+## Disk Performance
+
+Using `fio` — Flexible I/O Tester (https://github.com/axboe/fio) is an efficient way to test the disk performance.
+You can find some samples here:
+
+* [Sample FIO Commands for Block Volume Performance Tests on Linux-based Instances](https://docs.oracle.com/en-us/iaas/Content/Block/References/samplefiocommandslinux.htm)
+* [How to use Fio (Flexible I/O Tester) to Measure Disk Performance in Linux](https://dotlayer.com/how-to-use-fio-to-measure-disk-performance-in-linux/)
+* [How to Measure Disk Performance using Fio in Linux](https://linoxide.com/measure-disk-performance-fio/)
+
+Cannot understand the options specified in the samples above? You can check the command line options and job file parameters here: <https://fio.readthedocs.io/en/latest/fio_doc.html>.
+
+## References
+
 - Stanislav Příhoda, "Elasticsearch Disk and Data Storage Optimizations with Benchmarks", _coralogix.com_, 2021.<br>
   <https://coralogix.com/log-analytics-blog/elasticsearch-disk-and-data-storage-optimizations-with-benchmarks/>
 - Elasticsearch, "How to design your Elasticsearch data storage architecture for scale", _elastic.co_, 2021.<br>