SOLVED Should I change my drives soon?

[Arvi LEFEVRE]

Hello!

18 months ago I built my NAS with Freenas, with 3 HDD in raid z1. The problem is the more I read about it (and raid5), the less I feel comfortable about my data, especially that I bought Desktop HDD from Seagate at 7200 rpm.

So, I was thinking maybe I should change my drive before something goes wrong (I don't want a 2nd drive to fail while I rebuild the raid...), so do you think I should change my drive in 6 months (I've almost never had any problem with HDD in the past, but well, you never know).

If I change, if I replace by three 4TB WD Red, I should be able to increase my pool right? And having different rotation speed (while I change) won't be a problem?

Thank you :)

 

[Mirfster]

So, I was thinking maybe I should change my drive before something goes wrong (I don't want a 2nd drive to fail while I rebuild the raid...), so do you think I should change my drive in 6 months (I've almost never had any problem with HDD in the past, but well, you never know).

You could, but that still does not eliminate the vulnerability that is inherent with running RaidZ1.

If I change, if I replace by three 4TB WD Red, I should be able to increase my pool right? And having different rotation speed (while I change) won't be a problem?

True, it will increase available space. However, I chose to see it as you having more data to lose if that vDev goes down.

I will add that if you are maintaining regular backups and are not concerned with having to restore, then concerns are a little lowered.

Since you really never told us what size the "3 HDD in raid z1" are or your system specs, it is difficult to provide other options.

However, one thing I will toss out there is that if you were able to offload your data temporarily; it would be worth considering to rebuild your Pool/Volume using those 3 old drives and the 3 new drives in a new RaidZ2 vDev instead.

 

[Arvi LEFEVRE]

Oh yeah, sorry, I have three 3 TB HDD right now.

Or maybe I should buy 2 4 TB (or bigger) HDD (I have 6 HDD spaces total, so 3 empty spaces now), I currently have 2.9 TB of data, move this to a new pool on a mirroring raid, and later buy 2 more 4 TB hdd to increase the size.

I guess I could find a way to put the data somewhere else (even for mirroring, I could reuse my 3TB drives that way with six 3TB HDD) and build a raidZ2, but I read in many places (like here: http://jrs-s.net/2015/02/06/zfs-you-should-use-mirror-vdevs-not-raidz/) it was better to do mirroring.

I have 16 GB of Ram, cpu is an intel G 3258.

 

[Mirfster]

I guess I could find a way to put the data somewhere else (even for mirroring, I could reuse my 3TB drives that way with six 3TB HDD) and build a raidZ2

IMHO that would be the preferred route. However, do note that two of the drives will be used for Redundancy with RaidZ2. So, you will not be gaining as much space as one may think.

Checkout @Bidule0hm 's Calculator for some space estimates: https://forums.freenas.org/index.php?threads/zfs-raid-size-and-reliability-calculator.28191/

As far as Mirror vDevs go, nothing is wrong with doing that either. But (there is always a "but"), you have to understand that this still is in the arena of each vDev only having one drive redundancy as well as the cost of only getting 50% of the space. I run some Mirror vDevs (for performance), but do offset the redundancy by having a "Hot Spare" for every 2-3 Mirror vDev. Others run 3-Way Mirrors which is even better, but again that is at a much higher cost since you are allocating 2 out of 3 drives to redundancy and only yielding one drive worth of usable space.

Tons of ways of designing your Pool/Volume using vDevs, it is just up to you to decide the best mix of Speed, Space and Redundancy that suits you.

Take a little time to mull it over and put thought into it. I promise it will be worth it in the end.

 

[Arvi LEFEVRE]

OK, thx for your input, I might make a raidZ2 then, I'll think about it :)

 

[Jailer]

You say you are concerned about your drives. Are you conducting regular smart testing and scrubs and has something shown up to raise a concern?

 

[Arvi LEFEVRE]

No, I'm concerned because I bought relatively cheap drive made for a Desktop computer. I actually haven't checked smart or scrub, just default settings, I assumed (and I should be more careful) it would do the basic and warned me if something is wrong, maybe I should have a look!

 

[Mirfster]

No, I'm concerned because I bought relatively cheap drive made for a Desktop computer. I actually haven't checked smart or scrub, just default settings, I assumed (and I should be more careful) it would do the basic and warned me if something is wrong, maybe I should have a look!

Have a look at the links under "Recommended Reading", namely these two:

DrKK's: How-to: First Configuration for Small FreeNAS Deployments
Bidule0hm's: Scripts to report SMART, ZPool and UPS status, HDD/CPU T°, HDD identification and backup the config