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Welcome to TrueNAS SCALE - Beginners Intro

Since mid 2021 we have had many new users of TrueNAS wanting to try SCALE. Here are some things that are helpful for new TrueNAS SCALE users to know;
  • TrueNAS SCALE is based on Linux, while TrueNAS Core uses FreeBSD, and uses different user land packages
  • Both SCALE & Core only use ZFS for data storage. If you are looking for something disk compatible with MS-Windows, look elsewhere. (But network accessible from MS-Windows is a fully supported feature.)
  • SCALE is a specialized & targeted OS based on Linux, so installing additional packages on the base OS will likely lead to frustration as they will disappear during an update
  • TrueNAS, both SCALE & Core, use dedicated boot devices:
  • SCALE is still under development, so some features may not be complete or fully functional, even as of 2023/09/25
  • One key difference between Core & SCALE is that SCALE can use Apps based on Kubernetes. This allows containerized programs to be more easily deployed, than Core's Jails, Plugins or VMs. But, it is still a work in progress, (and Kubernetes is NOT Docker).
  • Users with questions or in need of support for TrueCharts should perform basic research on the website;
    Then if needed, ask questions in the Discord channel;
  • SCALE Bluefin added a “hostPathValidation” setting for App access to host data. See:
  • With SCALE based on Linux, the ZFS ARC, (Adaptive Read Cache), will act differently than on Core, (which is based on FreeBSD). Linux users can increase their ARC size to a larger percent of RAM, because Linux uses a fixed percent of memory for ARC. Not all un-used memory like FreeBSD.
  • Just because SCALE is based on Linux, random / recycled / old hardware may not work faster or more reliable than Core. A good NAS server will want to be reliable & protect your data, which random, recycled or old hardware may not do.
  • SCALE is not an upgrade from Core, they are similar products with slightly different feature sets
  • Core will likely be a bit more stable than SCALE, due to difference in kernel development procedures. Further, Core has had many years of work to make it stable, reliable & fast, where SCALE is a spring chicken by comparison.
  • TrueNAS does not support sharing storage devices between vDevs or pools, except spares.
  • YouTube is generally entertainment, so take any ZFS or TrueNAS videos with a lump of salt. But, running a production NAS server is generally not entertainment, even if it is for your home.
  • Why did you select SCALE & ZFS?
    Just because others show it is easy, does not mean it will be easy, and appropriate for you. Here is a helpful introduction to ZFS:
  • ZFS pool & datasets are different enough, that unless you know the basics, you can make some serious mistakes. Some mistakes will require a full backup and restore to remedy. See this helpful guide:
  • Just because "it works" after install does not mean that your TrueNAS SCALE server will be reliable in the long run. Or even in the short run. A properly designed, configured and parted out NAS server will generally be reliable. But, many people throw parts together and assume they are suitable. Which may not be the case.
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Nice job -helpful. I did have a question about:
"ZFS pool & datasets are different enough, that unless you know the basics, you can make some serious mistakes. Some mistakes will require a full backup and restore to remedy. See this helpful guide:"
IIUC this applies to both CORE and SCALE, i.e. it's a ZFS thing? Or Am I missing something. I'm reading because I am deciding if it is safe for me to switch to SCALE.
This comment applies to both SCALE & Core. I made it because their are now more SCALE users building non-redundant pools without knowing the risks. (Their are some who know the risks...)
It's solid information, though not really a guide...
Your right, I've changed the "Guide" word to "Intro", though that still might not be the final word.