Add another VDEV with different capacity disks?

[helloha]

Hi,

this is what my current pool looks like.

2 vdevs of 5 4TB drives in RaidZ1. 10 Drives in total.

I have another 6 3TB drives laying around.

Can I add them as another Raidz1 vdev to the same pool?

Will they just grow the pool and will the IOPS increase because I then would have 3 VDEV's?

Cheers!
K.

Code:

TSW-POOL                                27.4T  8.82T      0      0      0      0
  raidz1                                13.7T  4.41T      0      0      0      0
    gptid/ba1cad14-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/bb1c2688-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/bd82473b-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c065d424-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c1ef3da9-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
  raidz1                                13.7T  4.41T      0      0      0      0
    gptid/c2f281d1-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c3f778ab-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c501cf66-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c61123af-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
    gptid/c71afb27-e44f-11e4-8cd6-001f2954783c      -      -      0      0      0      0
cache                                       -      -      -      -      -      -
  gptid/c7a86084-e44f-11e4-8cd6-001f2954783c  29.2G   209G      0      0      0      0

 

[danb35]

Sure you can, and yes it will grow the pool (see my sig). That many high-capacity disks in RAIDZ1 is asking for trouble, though.

 

[DrKK]

I agree with danb35. You can do it, but I would certainly never recommend 5x4TB disks in RAID-Z. That's a bit more risky than the (ultra-conservative and risk-averse) FreeNAS community would ever suggest to a user.

 

[helloha]

That's why is was suggested by those renegade hipsters at the nas4free forums :)

It's only an onsite backup that is used by an assistant. So in this usage scenario I don't really need raidz2 but I do need some half decent IOPS. That's why I went this route.

But I moved to freenas because I was having too many issues with disk alignments and slow networking etc...

 

[helloha]

Out of curiosity, will ZFS redistribute the data once I add that additional VDEV?

Or will the existing data stay on the existing 2 VDEV's and the new data I add will go to the new VDEV?

K.

 

[Robert Trevellyan]

Out of curiosity, will ZFS redistribute the data once I add that additional VDEV?

Or will the existing data stay on the existing 2 VDEV's and the new data I add will go to the new VDEV?

Data you add or change will be distributed among the vdevs (remember, ZFS is a copy-on-write filesystem.)

 

[helloha]

So the existing data will stay on the 2 vdevs not really increasing my iops?

K.

 

[Robert Trevellyan]

Unmodified data will stay where it is. If you want to force redistribution, you can move things between datasets, or off the NAS and back on.