u/Aggravating-Smile-10

Hi everyone, I’m new to the ZFS/TrueNAS world. I just finished building my DIY homeserver (which I honestly think is kind of a beast 😅) and in the next few weeks I’ll probably share the full setup on the homelab/homeserver subreddits.

A bit of context first:

I currently have a total of 12x 4TB SAS 3.5" 7200RPM drives. Right now I only have 8 installed in the server and I keep the other 4 as replacements because these are used enterprise drives with a lot of power-on hours.

The server itself has 256GB RAM and dual Xeon E5-2640v4 CPUs, although initially I’ll only run part of the hardware to reduce unnecessary power consumption (x1 CPU and 128GB ram).

The server runs Proxmox and I’m planning to deploy TrueNAS on latest stable version in a VM with passthrough of a Broadcom LSI 9305-16i HBA where all drives are connected. Initially I was thinking about assigning 32GB RAM to TrueNAS, although I’m not sure if that’s enough or if 64GB would make more sense.

Out of those 8 installed disks, I’m thinking about initially using only 4 drives in RAIDZ2 because right now I only have around 700GB of data on my current Synology DS213. I still need to clean up a lot of old residual files that have accumulated over the years, so after sorting everything out the actual amount of important data will probably be closer to 550-600GB.

Starting directly with 8 drives feels a bit wasteful in terms of power consumption, heat and drive wear for storage capacity that I realistically won’t need initially.

The idea is to grow progressively over time as the homelab grows with:

• multimedia
• movies and TV shows
• self-hosted services
• backups
• repositories
• etc.

My main priority is data safety.
Then power consumption.
And finally reasonable performance.

From what I’ve understood so far:

• a 4-disk RAIDZ2 still keeps 2-disk fault tolerance.
• the “inefficiency” of small RAIDZ2 pools seems to be more about usable capacity than actual safety.
• and TrueNAS now supports RAIDZ expansion by adding disks progressively.

But honestly, the thing that scares me the most about this whole project is exactly that:
expanding the RAIDZ2 later from 4 disks to 6 or even 8 disks as my storage needs grow.

I’ve been reading forums and opinions seem very divided:

• some people say RAIDZ expansion works perfectly fine
• others recommend creating the final vdev layout from day one and never touching it again
• and others say it’s already mature enough for homelab use

So here comes my real question:

- Is this actually risky?
- What real dangers or downsides are there when progressively expanding a RAIDZ2 pool?
- Is the community still conservative because the feature is relatively new, or are there genuinely important risks during expansion?

I’d also really like to know what you would personally do in my situation:

• start with 4 drives to save power and drive hours?
• or build the final 6/8-disk RAIDZ2 pool from the beginning?

I’m completely new to ZFS and TrueNAS, so any advice or best practices are more than welcome 😄

Thanks everyone!