There are highly optimized installation packages (for 32 Bit bullseye/bookworm and 64 bit bullseye/bookworm) with release versions and regular builds of the development branch.

The SCSI2Pi binary package is installed in a matter of seconds:

>sudo apt install ./scsi2pi_BUILD_ARCH.deb

A warning like "Download is performed unsandboxed as root" can be ignored.

After the first installation you should check and adjust the default settings in /etc/s2p.conf, e.g. the default path for drive images.
During the installation the PiSCSI system service, if active, will be deactivated. The SCSI2Pi system service will be created instead. The standard installation path of the SCSI2Pi binaries and manpages is /opt/scsi2pi. You should add this path to your environment, e.g. in .bash_profile:

export PATH=/opt/scsi2pi/bin:$PATH
export MANPATH=/opt/scsi2pi/man:$MANPATH

SCSI2Pi is de-installed with:

>sudo apt remove scsi2pi

SCSI2Pi is compatible with the PiSCSI web UI, which you can install before or after installing SCSI2Pi. Thus SCSI2Pi just like PiSCSI can also be managed with a browser. Note that the PISCSI and SCSI2Pi system service cannot be running at the same time.
The SCSI2Pi configuration according to the usual standards is managed in the file /etc/s2p.conf and not like with PiSCSI in the startup file for the system service.

You can also compile SCSI2Pi yourself, e.g. for a customized build. The SCSI2Pi wiki provides more information.

1. Download the suitable SCSI2Pi package and install it with sudo apt install ./scsi2pi_BUILD_ARCH.deb.
2. Create virtual devices with properties in the configuration file /etc/s2p.conf, e.g. with sudo vi /etc/s2p.conf.
3. Restart the system service with sudo systemctl restart s2p.
4. You can also attach devices with the PiSCSI web interface, the SCSI Control app or s2pctl.