Setup for 6 drives with 2 spares (4+2)

[markomo]

Hi all, I am total nob and just have hardware ready for setup (did a test installation) and I will need an advice for setup.
There are a lots of questions and answers to similar questions.

I am looking into setting up TrueNas with 6 drives (if that's better option) with size of 8 TB (best value for the money). I am not looking for big capacity and not care much about usable space. I would be okey with 20-24 TB at the end and for longer term.
I have music, photos, my main PC weekly backups to store. Speed is not important that much, I have 1 Gb network so does not really matter overall.

I am looking more for data integrity and less chance to loose data (with any configuration up to 6 drives * 8 TB.
What I've found RAIDZ2 would be best option. I am wondering how should I setup my pool(s)? I am thinking of 4 + 2 drives; 4 data and 2 cold spares or .. I am new in this but do not want make big mistake in choosing optimal option.

I have PC ready with 32 GB RAM, RAIDZ2 should not be a problem. Thanks in advance!

 

[c77dk]

When you have a total of 6 drives, just put them all in one raidz2 vdev (and do proper burn-in). That would give you about 22TiB usable space.

 

[markomo]

That sound like a good plan. I am not exactly sure what redudancy I get and what (which) drive can fail without having data lost. Replacing drive procedure and all of that. I am not sure what burn in means and how to do it / what it does. I want to keep backups on it, music and photos (which is important). Thinking about getting another 8 TB drive for cold copies for what's important and can't be lost in any case.

Just thinking about how long will it actually last; it won't be under any heavy load and usage.

I am thinking to add two SSD-s and use them for VMs. Will that work without problem as different vdev? It should not effect performance.
Main system drive is m2 gen 3, that should run quiet good. I want it to run at least 3-4 years hopefully.

Another question on top of this; I have some older mixed drives (wd green, wd black, seagate baracuda and all 2 TB in size). Adding them as a another pool should work and would not effect performance of the 6 drive raidz2?

 

[danb35]

I am not exactly sure what redudancy I get and what (which) drive can fail without having data lost.

Really, you should do some reading on ZFS to understand this, but with RAIDZ2, any two drives can fail without data loss.

Replacing drive procedure and all of that.

/core/coretutorials/storage/disks/diskreplace/

I am not sure what burn in means and how to do it / what it does.

fester112:hvalid_hdd [danb35's Wiki]

www.familybrown.org

 

[sretalla]

with RAIDZ2, any two drives can fail without data loss.

I had done the mapping for that and come up with a picture to help to explain that. Maybe it will help.

On the X and Y axes you have drives (A-F) one drive failing on each axis, then red for VDEV/pool loss and yellow for degraded VDEV/pool as a result:

 

[markomo]

Guys thanks for putting all this together, after a bit research I do have better understanding how it works. I would for example create one vdev and only one pool and create datasets on it to give a little bit of access to shared folders etc.

I guess that's how it could be (in my case with 6 drives) setup. I'll do some research how to mark drives properly so I know which should be replaced (taken out from the PC box) if it fails. I would appreciate any recommendation on this.

 

[Stux]

Yes, basically, you just want 6 drives in RaidZ2. No need for hot spares at that scale.

RaidZ2 is not really porformant if you plan to use a lot of VMs, but you have not indicated that, but for general file storage, its perfect and you would have to have 3 colocated block failures to lose data, which is unlikely. Just replace a disk as soon as you can if it fails, and make sure you're running SMART tests for early warning.

EVERTHING you do will come out of the one pool of storage. One day, if you want more storage, you can replace every drive (one at a time) with larger drives... OR add another 6 drives as another vdev of RaidZ2

BUT you do need to backup anything important. Ie, anything that you would want to have *if* the worst happens and you lose your pool.

Redundancy in not a backup. A backup is.

Regarding marking drives, I find the best way is to label the drive or bay, with the last 4 or 5 digits of the serial number. Then you can see the serial number in the gui, and you know which bay it refers too.