Expand With Mirror or RaidZ

[Soloam]

Hello all, at the moment I have a system with RaidZ2 with 4 2TB HDD, but I'm starting to have problems with storage. My system:

Supermicro X10SL7-F IT Mode - Intel Xeon E3-1231 V3 - Crucial 32GB DDR3 1600MHz ECC
4 x WDRed 2TB RAIDz2 (Main Storage) - 1x WDGreen 2TB (External Backups) - 1x WDGreen (Trash Files)

I what to have more space to media files (movies etc)... Basically things that I can easily rebuild if I lose them, but that I want to avoid, so a minimum of redundancy is required.

This are my options:

1. 3x WD Red 2TB - RAIDz - 4TB Space
2. 2x WD Red 4TB - Mirror - 4TB Space

(Space in the Case is not a problem, and aloso Sata ports are not a problem).

In value, they are both very similar, I can get 3 2TB HDD for almost the same value of 2 4TB. What is the best option in your opinion?

I was leaning to the 2x 4TB just because if in the future I would want to boost my main RAIDz2 Pool, I could move this 2 4TB drives and get only 2 more. But if there are real advantages I would go with the 3x 2TB RAIDz.

Thank you

 

[garm]

Don’t mix vdev topology in the same pool

For a new pool I would opt for the mirror option as the RAIDZ1 option is less reliable in my opinion (double the risk of loss of pool during resilvering)

 

[Soloam]

Thak you @garm, so in you opinions, If I can't go RAIDz2, I should go with mirror? Is that it?

 

[garm]

I’m in the minority on this forum, but I prefer mirrors over RAIDZ. Especially for pools under say 6 drives.

 

[Heracles]

Hey Soloam,

Would it be an option to empty your actual pool and build a new RaidZ2 pool with all of your 6 4TB drives ?

That would be strong protection and a lot of space. It would increase your space by 100% of the new drives instead of a fraction.

But for that, you need to empty and destroy the actual pool....

 

[Soloam]

I don't have 4TB drives... I have at the moment 4 x 2TB drives in a RAIDz2... I was planning on adding more space to media files (downloaded), so not very crucial information (but I would like some protection, just to avoid rebuild everything if I lose a drive). My idea was buy:

1. 3x WD Red 2TB - RAIDz - 4TB Space
2. 2x WD Red 4TB - Mirror - 4TB Space

But I'm open to new ideias, as long as the price is more or less in this limits (both solutions are more or less the same value).

Thank you

 

[Heracles]

My bad about the 6x 4TB...

Still, would it be an option to make a 6 drives RaidZ2 with your 4x 2TB and 2x 4TB ? It is true that at first, your new 4TB drives will be used only as 2TB drives, but that will prepare your pool for the auto-expand feature.

Slowly, you can replace one 2TB drive at a time and resilver the pool after each switch. When your last 2TB will be replaced, ZFS will automagically expand your pool and uses the full 4TB on each drive.