Raid-Z3 vs. Raid-Z2 + Spare

[moda]

Hello,

In my new build I have 8x 6TB HGST Drives available, now I am wondering if it is better to arrange the array in a Raid-Z3 configuration (8x6TB) or a Raid-Z2 configuration with one available spare (7x6TB + 1x6TB spare). As to the Reliable RAID Configuration Calculator I would get a lower Zpool failure probability with the Raid-Z3 configuration, are there any downsides to this?

Thanks in advance

 

[sretalla]

If you're going to use a spare, you might as well have it already resilvered (=Z3)... it's spinning anyway as a spare unless you keep it as a cold spare.

You take a small write penalty with Z3, but probably won't notice as it's already in a RAIDZ setup, so essentially IOPS of one disk per VDEV.