Which Raid should I use for 4x2TB HDD?

[nichohagan]

Hi everyone,
Today is my 3rd day of using TrueNAS, and it's very new to me. I have 4 HDDs (WD Red NAS), with each drive being 2TB. I have plans to add more drives (about 6 more) to the pool. I am contemplating on which Raid to use (Raid 5 or Raid 10).
Which Raid should I use for my pool setup? Thank you.

 

[rvassar]

You should probably start with the ZFS primer and get some nomenclature & background. ZFS doesn't implement "RAID 0/1/5/6/10" quite the same as traditional storage. It implements storage pools on top of RAIDz1, RAIDz2, stripes & mirrors, all of which can have multiple vdev's, and your data resides in datasets on top of those pools. The datasets themselves can have additional properties. Since you plan to add disks, you'll want to spend some time and get it right at the start. You can expand a pool by adding a matching vdev. Your 4 x 2Tb can become 2 x (4 x 2Tb), but not a 8 x 2Tb, and you can't migrate from RAIDz1 to RAIDz2 like a HW RAID controller, etc...

Introduction to ZFS

Beyond that, we need info on what kind of workload you're expecting, and what sort of redundancy you require. Forum etiquette also require you to describe your hardware config, CPU / memory, etc...

Welcome!

 

[Arwen]

Also, Welcome to the world of ZFS & TrueNAS!

One thing to know about Western Digital Red NAS disks, is they did something nasty. Please check your 4 x 2TB HDDs (WD Red NAS), and make sure they are CMR, (Conventional Magnetic Recording). If they are SMR, attempt to return them as soon as possible. SMR, (Shingled Magnetic Recording), type of hard disks, especially from Western Digital, are not friendly to ZFS.

Here are some Forum Resources on the SMR / CMR subject;

List of known SMR drives

Hard drives that write data in overlapping, "shingled" tracks, have greater areal density than ones that do not. For cost and capacity reasons, manufacturers are increasingly moving to SMR, Shingled Magnetic Recording. SMR is a form of PMR...

www.truenas.com

Scripted Detection of SMR Drives

This resource was originally created by user: Basil Hendroff on the TrueNAS Community Forums Archive. Please DM this account or comment in this thread to claim it. SMR technology is a timebomb waiting to go off in a ZFS file system. This quote from Slashdot… At absolute best, SMR disks...

www.truenas.com

 

[nichohagan]

Also, Welcome to the world of ZFS & TrueNAS!

One thing to know about Western Digital Red NAS disks, is they did something nasty. Please check your 4 x 2TB HDDs (WD Red NAS), and make sure they are CMR, (Conventional Magnetic Recording). If they are SMR, attempt to return them as soon as possible. SMR, (Shingled Magnetic Recording), type of hard disks, especially from Western Digital, are not friendly to ZFS.

Here are some Forum Resources on the SMR / CMR subject;

List of known SMR drives

Hard drives that write data in overlapping, "shingled" tracks, have greater areal density than ones that do not. For cost and capacity reasons, manufacturers are increasingly moving to SMR, Shingled Magnetic Recording. SMR is a form of PMR...

www.truenas.com

Scripted Detection of SMR Drives

This resource was originally created by user: Basil Hendroff on the TrueNAS Community Forums Archive. Please DM this account or comment in this thread to claim it. SMR technology is a timebomb waiting to go off in a ZFS file system. This quote from Slashdot… At absolute best, SMR disks...

www.truenas.com

Thank you @Arwen. Fortunately, my drives are CMR (the code is WD20EFRX) and I checked with the link you shared and luckily, they are. Thank you for that information though because it is going to help in my future upgrade.

 

[Davvo]

Consider reading the following resource:

ZFS Storage Pool Layout

This resource was originally created by user: @Davvo on the TrueNAS Community Forums Archive. https://www.truenas.com/community/resources/zfs-storage-pool-layout.201/download [1] This amazing document, created by iXsystems in February 2022 as a “White Paper”, cleanly explains how to qualify...

www.truenas.com