12x3tb raidZ suggestion

[Fermin Rodriguez]

i searched around and found 14 drive and 10 drive recomendation
but none of them for 3tb drives.
the order of importance is space, perfomance and repair/restore time in case of hard drive failure.
suggestions?
perhaps 2 vdevs of raidz1 each?
i know cyberjock would do 2 vdevs of raidz3 each. but im not willing to loose 18tb of space just to feel tripple safe

 

[Darren Myers]

So then do 2 RAIDz2's of 6 drives each?

 

[Fermin Rodriguez]

is it a single raidz3 or 2 raidz1 of 6 each the same as calling the devil?
i dont think i should prepare myself to lose 2 drives :S

 

[Darren Myers]

well typically 11 drives is the max that should be used.... a RAIDz2 gives you the fault tolerance of 2 drives, so depending if you strip the 2 together is your choice but would yeild you a boost in speed, otherwise 2 separate vdevs of 6 drives each gives you 9.4Tb usable per vdev, so you would in theory have ~19Tb usable across both. RAIDz2 is now the preferred RAIDz for drives larger then 4Tb , but i would certainly do it with anything larger then 2Tb just because you may want to expand the pool without destroying it.

 

[Fermin Rodriguez]

in other words a single pool on raidz2 with one "hot spare" is encouraged over a single pool with all 12 drives?

 

[Darren Myers]

Typically RAIDz2 is 4,6,8,10 might be push-able to 12 drives for a single vdev, RAIDz3 is 5,7,9,11 in a single vdev. I'm not sure if ive come across any posts of someone using 12 drives in a single vdev.

Give this a read https://forums.freenas.org/index.php?threads/why-optimal-number-of-disks.28318/#post-184501

 

[Bidule0hm]

This is outdated if you use compression (and you likely are as it's the default), don't worry about the number of drives per vdev as long as you're under the 11 drives limit.

RAID-Z1 is very not recommended for drives bigger than 1 TB.

Given what you've said, I'd say 2x RAID-Z2 of 6 drives is the best for you.

 

[Robert Trevellyan]

the order of importance is space, perfomance[sic] and repair/restore time in case of hard drive failure.
2 vdevs of raidz1

Based on your priorities, I agree with your selection. You don't list MTTDL as a priority at all, which is what would indicate RAIDZ2 or RAIDZ3. Consider using the 13th drive as a hot spare for both vdevs to somewhat mitigate the risk associated with RAIDZ1 on large drives, and make absolutely sure you have your email notifications and SMART checks and tests working correctly.