Installed TrueNAS, created pool... now what?

[DaddyShack]

Success, Huzzah! I've got a functional TrueNAS-13.0-U4 system!

I've cobbled together some recently retired hardware and refreshed it with new drives to replace an old FreeNAS system that spectacularly and catastrophically died a decade ago. And gosh has stuff changed. It was GELI, GRAID, and NFS back then. ZFS and iSCSI were new esoteric things that were in beta and just starting to be mentioned and adopted. I'm kind of an old dog trying to learn new tricks here.

I'm looking for some guidance for my next steps. I feel like the choices I make here are kind of dependent upon and could have complicated, possibly detrimental effects towards my end goals.

I'm not sure I completely grasp the concepts of Datasets and Zvols. I feel like I'm at the point that I conceptually understand of creating filesystems and mount points. Divvying up the "pool", if you may, for specific purposes and functions. So I'll try to focus my primary goals right now and listen to what other people consider and do at this point of configuration. I don't want to make any ignorant and short sighted decisions that would be difficult or laborious to rectify down the road.

My current desired goals and objectives:

Replace a Time Machine/AirPort Extreme device on my network to service Time Machine backups for my networked Macs.
Create a network accessible storage location to store digital copies of all the movies I've purchased through iTunes, ideally to be accessible with my Apple TV.
Create network accessible storage for myself and my children to have their individual directories/mount points.

Secondary goals and objectives:
Possibly create a remotely accessible "cloud".
A request from one son -- Minecraft server? That's a soft no... maybe a separate dedicated specialized server NAS for another day.

I set my pool of drives up as raidZ2. It netted approximately 6.92 TiB Free. It may not be enough to store the collection of my movies. But I figured I would get this thing set up and cross the bridge of sliding in larger capacity drives if I need to cross that bridge down the road. That's part of where my ignorance comes in. Some of what I'm reading says that expanding is not possible, something about being immutable. I want to avoid having 5 TB of data with the only option of migrating to a larger space being to build a whole new NAS from the ground up to migrate to. Am I locking myself into a 7 TiB "volume"?

Thanks in advance for any consideration, guidance, and advice.

 

[jgreco]

I've cobbled together some recently retired hardware and refreshed it with new drives to replace an old FreeNAS system that spectacularly and catastrophically died a decade ago.

Welcome back. Sorry to hear about the previous failure. A lot of times this comes from hardware selections, and, if you wish, you can post your current hardware for a critique. Only if you can accept constructive criticism though. ;-) We're all about data reliability over the long term, because when you have a filesystem that can easily store a petabyte but doesn't have a fsck command, you gotta remember that the trick is keeping the system reliable.

I'm not sure I completely grasp the concepts of Datasets and Zvols.

A pool is a set of vdevs that make up a "pool" of storage; usually small systems only have a "boot" pool for the OS and then a "data" pool for your storage. Datasets are subsections of the data pool and are basically along the lines of a classic UNIX disk partition, except that the "partition" doesn't have a fixed location or size. You could have a 1TB data pool and then allocate a bunch of datasets inside it. You go into dataset A, write 900GB, remove that, go into dataset B, write 900GB, and that works (much to the shock of anyone who's partitioned disks on a conventional UNIX or Windows box).

Zvols are exclusively for block storage such as iSCSI or VM disk storage. If you are not using those things, FUGGEDABOUTIT!

I set my pool of drives up as raidZ2. It netted approximately 6.92 TiB Free. It may not be enough to store the collection of my movies. But I figured I would get this thing set up and cross the bridge of sliding in larger capacity drives if I need to cross that bridge down the road. That's part of where my ignorance comes in. Some of what I'm reading says that expanding is not possible, something about being immutable.

What is that, then, RAIDZ2 and 6.92TiB sounds like you maybe have four 4TB drives in a RAIDZ2?

You can do two things:

1) You can replace each 4TB HDD with a larger HD such as the commonly available 12-18TB's. The array rebuilds after each replacement and when you get to the last drive, a huge amount of free space opens up.

2) You can add a second vdev with drives of whatever capacity you find convenient. It should be a RAIDZ2 vdev (doesn't HAVE to be but you may end up with buyer's remorse). Space becomes immediately available.

You CANNOT add more hard drives to your existing vdev, though. RAIDZ expansion will be supported, someday, maybe by the time I'm dead in 2060.