What's the difference between Streaming read/write speeds and read/write IOPS?

[phao5814]

I'm new to FreeNAS so I'm taking the time to read the following article:

Six Metrics for Measuring ZFS Pool Performance Part 1 - TrueNAS - Welcome to the Open Storage Era

Learn more about why OpenZFS (ZFS) storage pool layouts have such a significant impact on system performance under various types of workloads.

www.ixsystems.com

The article mentions the following:

To quantify pool performance, we will consider six primary metrics:

• Read I/O operations per second (IOPS)
• Write IOPS
• Streaming read speed
• Streaming write speed
• Storage space efficiency (usable capacity after parity versus total raw capacity)
• Fault tolerance (maximum number of drives that can fail before data loss)

However, it doesn't really explain what streaming read/write speed means. What does "streaming read/write speed" mean and how does it differ from IOPS?

 

[artlessknave]

I believe in this context streaming read/write is a small number of larger files, like video files, or a small number of simultaneous read/writes, like with a single user, that can be generally written in a consolidated collection of writes - streamed.
high IOPS means being able to do a large number of operations at the same time, usually with a large number of small files, or with a large number of users.
streaming speeds works best for things like plex or video editing, while high IOPS works best for things like VM's or databases. you would need both high streaming speed and high IOPS to do something like multiple video editors.
raidzX typically gives the best streaming speeds, while mirrors typically gives the best IOPS, though IOPS can be increased by having more vdevs.