ESXi 6.5 Slow performance

If ESXi disk performance is slow it might be because it uses it's own native driver

[root@localhost:/] esxcli software vib list | grep ahci
sata-ahci                      3.0-22vmw.650.0.0.4564106             VMW     VMwareCertified   2018-09-03
vmw-ahci                       1.0.0-34vmw.650.0.14.5146846          VMW     VMwareCertified   2018-09-03

The native driver vmw-ahci is known to slow disk performance down

Disable the vmw-ahci" driver with

esxcli system module set --enabled=false --module="vmw_ahci"

NOTE: The underscore and not dash in drivername! check with

[root@localhost:~] esxcli system module list | grep ahci
ahci                                true        true
vmw_ahci                       false       false

Reboot the esxi server - and hopefully, it works and is faster now.