Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
How much vRAM have you given the Solaris VM. The more the better. Do you have any idea how big your "working set" is. An example is a Win7 VM, thats 40GB on disk. So the working set could be as much as 40GB to be cached in full. WinXP is merely 8.
Add more RAM. 10x if you can. 16GB just isn't enough.
If thats not a complete enough of an answer keep reading. I have spent tens of thousands wading through the morass of poor zfs performance regarding ESXi that I finally get it.
Add more RAM. As much as you can possibly squeeze into...