ESXi CARP on selected interfaces

[klatoszy]

I have been running pfSense in ESXi VM with success for years. Recently when 2.4.5 was released I decided that I will add another VM and configure CARP to avoid down time during upgrade and/or other maintenance work. I'm using free ESXi version and thus only standard virtual switch is available.
I followed documentation and CARP is running perfectly fine. But due to ESXi standard switch limitations (traffic goes to all VMs in portgroup) I have a problem with additional traffic, specifically on VLAN with file storage traffic where huge amount of data are moved. This has big performance impact on hypervisor.
I have following interfaces:
WAN
LAN
MGMT
IOT
STORAGE
currently all configured for CARP. Big traffic on STORAGE interface affects heavily hypervisor.
Now my idea is following:
Configure CARP on all interfaces except STORAGE.
During failover execute script to enable STORAGE interface on Master and disable on Slave. Alternatively keep STORAGE interface UP on both nodes but add/remove VIP alias during failover.
Does this make any sense? Will that work? I don't mind if connections are dropped and/or STORAGE network will be down for few seconds.
Please advise.

[klatoszy]

So I investigated this littel bit further. Bringing interfaces UP/DOWN on failover did not work as expected.

Then I tried to use VIP alias. At first manually using SSH I invoked following commands:
VM becomeing Master:

ifconfig vmx6 10.79.60.1 255.255.255.255 alias

VM becomeing Backup:

ifconfig vmx6 10.79.60.1 255.255.255.255 delete

This gave me good result so I wanted to automate and edited /etc/rc.carpbackup and /etc/rc.carpmaster on both nodes. This did not work and I receive crash report like below:

Crash report begins.  Anonymous machine information:

amd64
11.3-STABLE
FreeBSD 11.3-STABLE #236 21cbb70bbd1(RELENG_2_4_5): Tue Mar 24 15:26:53 EDT 2020     root@buildbot1-nyi.netgate.com:/build/ce-crossbuild-245/obj/amd64/YNx4Qq3j/build/ce-crossbuild-245/sources/FreeBSD-src/sys/pfSense

Crash report details:

PHP Errors:
[25-May-2020 14:05:18 Europe/Warsaw] PHP Parse error:  syntax error, unexpected 'vmx6' (T_STRING) in /etc/rc.carpbackup on line 120
[25-May-2020 14:05:18 Europe/Warsaw] PHP Parse error:  syntax error, unexpected 'vmx6' (T_STRING) in /etc/rc.carpbackup on line 120
[25-May-2020 14:05:18 Europe/Warsaw] PHP Parse error:  syntax error, unexpected 'vmx6' (T_STRING) in /etc/rc.carpbackup on line 120
[25-May-2020 14:05:18 Europe/Warsaw] PHP Parse error:  syntax error, unexpected 'vmx6' (T_STRING) in /etc/rc.carpbackup on line 120
[25-May-2020 14:05:18 Europe/Warsaw] PHP Parse error:  syntax error, unexpected 'vmx6' (T_STRING) in /etc/rc.carpbackup on line 120

What I'm doing worng?