Hello everyone, I have a question about an unusual pool configuration. I have 4x 4TB WD Gold drives which I want to use for a pool with 2 mirrored vdevs. I also have a spare SAMSUNG 960 EVO 512GB NVMe SSD. Does it make sense to use this NVMe SSD as L2ARC for the pool? The server should host a Windows Server 2016 VM and also serve as a file server. I have 32GB DDR4 ECC RAM available and the OS is Ubuntu 18.04 Server LTS.
So do I use the NVMe SSD to put the VM on or do I put the VM on the ZFS pool using the SSD as L2ARC? =)
I would say use the NVMe as a L2Arc, then put the VM on the pool.
Then ZFS would cache the bits used more often.
But I don’t think it would need all the space, so might be worth making a partition on the SSD for the VM, and another for L2Arc.
Not sure of the exact figures, but I suspect if the whole drive was used as L2Arc, then it would fill the Arc in the ram with pointers to the L2Arc so much that you may end up loosing the benefit of the ram speed arc, at the gain of a slower L2Arc, which would still be much faster than the HDD pool.
But mostly I’m jealous because I can’t justify an NVMe drive cache myself 
NVMe drives are coming down in price, its coming soon!
I just found out, that 32GB RAM is not enough for a 500GB L2ARC so all I could do is usin g a smaller partition of that SSD for L2ARC … so never mind and sorry for your time ^^