A build for now, and down the road...

[Mike O]

Folks,

My first post... so please forgive any inherent newbie-ness.

Like many here, I've been playing around with my first FreeNAS server, and now I'm ready to get serious.

Currently, I've got 3 x 2.0TB SATA Drives available, and another 2.0TB & 1.0TB waiting in the wings (I won't be able to free the 2.0TB up for another couple of months though) to be used/integrated at a later date.

The system I'm playing with has 8GB RAM, 6 available SATA ports, and boots FreeNAS 9.2x off of a USB thumb drive. I've had a 2 x 2TB Stripe running for a while, so I know the hardware is all good.

What I need advice on is the planning. I want to build a server now with the 3 x 2.0TB drives... but with the knowledge that i will be adding to it in the next few months... scalability is the key.

Can I build a 3 x Drive server now, with some semblance of speed and availability, and add a 4th 2.0 TB drive later (and maybe a 5th?) and build up from that? Can the 1.0TB drive be used somehow to improve redundancy?

Thoughts? Suggestions? More information needed?

Thanks in advance.

 

[Spearfoot]

Folks,

My first post... so please forgive any inherent newbie-ness.

Like many here, I've been playing around with my first FreeNAS server, and now I'm ready to get serious.

Currently, I've got 3 x 2.0TB SATA Drives available, and another 2.0TB & 1.0TB waiting in the wings (I won't be able to free the 2.0TB up for another couple of months though) to be used/integrated at a later date.

The system I'm playing with has 8GB RAM, 6 available SATA ports, and boots FreeNAS 9.2x off of a USB thumb drive. I've had a 2 x 2TB Stripe running for a while, so I know the hardware is all good.

What I need advice on is the planning. I want to build a server now with the 3 x 2.0TB drives... but with the knowledge that i will be adding to it in the next few months... scalability is the key.

Can I build a 3 x Drive server now, with some semblance of speed and availability, and add a 4th 2.0 TB drive later (and maybe a 5th?) and build up from that? Can the 1.0TB drive be used somehow to improve redundancy?

Thoughts? Suggestions? More information needed?

Thanks in advance.

Hello, and welcome to the forums!

The most important question is: what do you intend to use your FreeNAS system for? Everything else pretty much follows from your answer to that question.

Starting out with 3 drives, about your only option is to make a pool with a single RAIDZ1-based vdev. This would give you the capacity of two drives, with parity using up the space of the third disk.

But RAIDZ vdevs (whether RAIDZ1, RAIDZ2, or RAIDZ3) cannot simply be expanded. You can only expand a pool (which is made up of one or more vdevs) by adding additional vdevs. TLDR: you can't just add another disk to a RAIDZ vdev.

You can always destroy the pool and recreate it with a new RAIDZn vdev made up of a larger number of disks, i.e., in your case going from 3 to 4 disks in a new RAIDZ1-based pool. But to take this approach, you must back up the pool data before destroying it, afterwards restoring the data from backup to your newly created pool. This shouldn't be a big deal because everyone ought to have good backups of their data... but you'd be surprised how many folks do not.

An alternative is to use mirrors. You could start out with a pool made up of a single 2-drive mirror, then expand the pool with additional mirrored pairs in the future. But mirrors aren't space-efficient; you only get half of the capacity of the drives.

You can see why it's easier to build your system with the full complement of however many drives you intend to use. But I understand how financial constraints can make this hard to do.

I'll leave you with a reading list that should help you get a handle on ZFS and FreeNAS:

https://forums.freenas.org/index.php?threads/zfs-primer.38927/
https://forums.freenas.org/index.ph...ning-vdev-zpool-zil-and-l2arc-for-noobs.7775/
https://forums.freenas.org/index.php?threads/comprehensive-diagram-of-the-zfs-structure.38865/
https://forums.freenas.org/index.php?threads/hardware-recommendations-read-this-first.23069/
https://forums.freenas.org/index.php?threads/building-burn-in-and-testing-your-freenas-system.17750/
https://forums.freenas.org/index.php?threads/how-to-hard-drive-burn-in-testing.21451/

Good luck!

 

[Dice]

Excellent @Spearfoot !

 

[Mike O]

Thanks for the detailed reply! Greatly appreciated...

So, I bit the bullet, and purchased an extra drive. I've now got 4 x 2,0TB drives available, and I'll be building the array this evening for, as I understand it, a combined usage of 6TB, with a basic redundancy built in... have I got that correct?

 

[BigDave]

I've now got 4 x 2,0TB drives available

I've found @Bidule0hm 's RAID Calculator to be very helpful when trying to make sense of this.
For some detailed understanding of ZFS's usage of your drives, you can read the thread connected
to the calculator at this link.

 

[Spearfoot]

Thanks for the detailed reply! Greatly appreciated...

So, I bit the bullet, and purchased an extra drive. I've now got 4 x 2,0TB drives available, and I'll be building the array this evening for, as I understand it, a combined usage of 6TB, with a basic redundancy built in... have I got that correct?

4 x 2TB drives in a RAIDZ1 vdev will give you the capacity of 3 drives, less overhead. So, yes - you'll end up with ~6TB of available capacity. The calculator linked by @BigDave will give a better approximation of the usable space you'll end up with.

 

[BigDave]

@Mike O
My posting of the Calculator link was by no means suggesting you skip
the six excellent links to a treasure trove of information that Spearfoot
has provided. I can not urge you strongly enough to read, before doing!!!

 

[Dice]

a combined usage of 6TB,

Press "Download now" to get to the relevant site:
https://forums.freenas.org/index.php?threads/zfs-raid-size-and-reliability-calculator.28191/

 

[BigDave]

Press "Download now" to get to the relevant site

I'm sorry, I tried to make that clear
Thnx @Dice :D

 

[Dice]

That was a mistake on my part. The browser tab did not "reload", thus did not show the typical message ~"want to read the new posts in this thread?"
My post was written prior to yours appearing, in spite of the hefty delay.
Only good intentions :)