Register for the iXsystems Community to get an ad-free experience and exclusive discounts in our eBay Store.

Raidz or mirrored?

juenoman400

Neophyte
Joined
Jan 13, 2021
Messages
4
Hello all,

I am new to this all and trying to learn as much as I can. I am sort of stuck on raidz2 or mirrored drives. I inherited a supermicro 24 bay case and 18 new 8Tb hard drives.

My intended usage for this server is to store my large collection of movies, My family photos and videos (very important), Music, and video game data. I also want my mac time machine saves to go here as well as windows backups. I plan to install emby in a jail and use it for media viewing on three televisions and three PC's. (Not all at the same time but, at times maybe three at a time will be in usage).. I don't plan to virtualize. The photos are very important to me so I purchased an external hard drive 8tb and I will set it up so freenas saves a copy there. (I have lots of reading to do). I am looking at about 14tb total once I put everything on this freenas box.). The photos and family videos are critical. Everything else I can lose, (I wouldn't be happy but I could live with it. Hopefully I wouldn't suffer a loss.). It would just take me a while to rip my movies and music again and get all the titles tags etc.


I have been reading over as much of the information here as I can trying to absorb it all.

1. How would all of you set this up? Would a raidz (I have read that raidz1 should be avoided )setup be best or would mirroring be a better path?
 

ee21

Member
Joined
Nov 2, 2020
Messages
33
Well it sort of depends on how you want to carve up your storage - or if you want to pool all the disks together.. Without knowing more about the disks themselves, I'm going to assume they are all identical models..

Assuming that, and taking what you have said into account, I would probably go for a pool with 3 vdevs, and use RAIDz2 (or z3 if you really want reliability) with 6 disks per vdev.. This would give you 66% usable space using z2, or 50% usable using z3..

Lets consider the alternative, you could create a pool with 9 vdevs of mirrors disks. This would give you 50% usable space, and the same 50% disk fault tolerance as the aforementioned RAIDz3 option - technically. The catch here is, you can only loose 1 disk per vdev, even if you could technically loose 9 disks total. If you did loose 1 disk, and were attempting a resilver, and for whatever reason the other disk failed or faulted, your pool would be lost.

If you were to create a pool with 6 vdevs of mirrored disks, and 3 disks per vdev, your usable capacity would plummet down to 33%, while affording a fault tolerance of 2 disks per vdevs, same as the RAID z2 option which allows you 66% total usable still.

The biggest upshot of a pool of mirrored vdevs I think you will see is performance. Based on your use case, and number of disks, I don't think you would notice a difference however.
 

juenoman400

Neophyte
Joined
Jan 13, 2021
Messages
4
Thanks for breaking that down for me! I should have listed my drives before. I have 10 Western digital reds (crm versions). And 8 Seagate ironwolf drives. All. 8 tb.

I think I will go with a raidz2 setup. I think I feel comfortable with that.

The empty drive bays, do I need to fill them asap or is it ok until I can save up for more drives?

I will continue reading the various recommended post and try gain as much as possible.
 

sretalla

Dedicated Sage
Joined
Jan 1, 2016
Messages
3,381
The empty drive bays, do I need to fill them asap or is it ok until I can save up for more drives?
If you plan to expand in future, leaving open bays is OK (make sure to blank them in to ensure airflow over your disks).

Make sure you have sufficient bays as with a RAIDZ2 pool, additional VDEVs will also need to be RAIDZ2, which means another 6 to make the next step.
 

ChrisRJ

Member
Joined
Oct 23, 2020
Messages
102
Not to say that you received bad advice so far, here is my take. I would not focus too much on "using up" all available drives right now, unless you need that much capacity immediately. Instead I would start with one RAIDZ2 pool of 8 or 9 drives (I have 8*16 TB here), which gives you a good amount of net space and redundancy. And when you start to fill up the roughly 45 TB net capacity you got this way, you can add an additional VDEV. This will save power in the meantime and allow you to stay flexible. I would probably recommend to test the speed (esp. for IOPS) before deciding for either approach
 

juenoman400

Neophyte
Joined
Jan 13, 2021
Messages
4
Thanks everyone. I am looking over everything. Later I will begin to set things up. Raidz2 is the path I will take.

In the future when I decide to fill the empty bays, do I need to purchase additional 8tb drives to maintain uniformity or can I get whatever size I choose?

I appreciate everyone's help.
 

sretalla

Dedicated Sage
Joined
Jan 1, 2016
Messages
3,381
In the future when I decide to fill the empty bays, do I need to purchase additional 8tb drives to maintain uniformity or can I get whatever size I choose?
I answered another thread with a post that would fit your question:
 
Top