I think CPUs are not as important, but RAM is. Disk Size... set it to somthing like "grow during use"

The installation script, at least in older versions, checks if the ESM started sucessfully, this takes more time if you have less RAM - and will fail.

I pulled this from the 7.6 Installation Guide

Processors 8 cores (16 preferred) 32 cores 40 cores
Memory 48 GB RAM (64 preferred) 192 GB RAM 512 GB RAM
Hard Disk Six 600 GB disks (1.5 TB)
(RAID 10)
10,000 RPM
20 1 TB disks (10 TB)
(RAID 10)
15,000 RPM
12 TB
(RAID 10)
Solid state

Thanks, Dale. I ended up being able to get an ESM running with 120GB disk, 16GB RAM, and 4 processors. It's not for production!

Hello David, 

the way that i preparing my VM lab is the following: 

4 x CPUs

16 GB RAM ( 32 recommended )

Disks :

 1 x 25 GB : necessary to deploy the OS /  CentOS/Rocky Linux or RHEL  - minimum install with the following required rpm: 

libnsl
ncurses-compat-libs
zip
unzip
libaio
libaio-devel
numactl

rng-tools ( starting with ESM 7.4 )

 1 x 60 GB : for /opt where the arcsight folder 

and that should be enough for an very small LAB to see the product be familiar with it but do not expect to persist more then few events.

For better results use the recommended env. from the install document. Those recommendation's are there for a reason.

I hope that will help you and later others for preparing an small lab .

Best Regards, 

Daniel