Modifying FreeBSD ISO for Dell Servers

Background

My NAS that I built in 2019 to host my files on my home network has started to show its age, especially as the number of services running in jails increased. It all started when I discovered the amazing features and data integrity that OpenZFS had to offer, and I tried out FreeNAS 11.2, which got released with a completely overhauled web interface at the time. Back then, I already had my media on Plex Media Server and learned that FreeNAS had Plex as a Plugin, which was my first contact with FreeBSD Jails.

Over time, I added more Jails on my NAS (e.g. Nextcloud, MineOS - a Minecraft Server Manager, UniFi Controller, …), which made me interested in learning more about Jails and FreeBSD itself. When some time later FreeNAS became TrueNAS Core and a few years after that, iXsystems decided to move forward with Linux, I migrated my NAS to FreeBSD. At the time of writing, the number of jails on my FreeBSD system has increased to almost 20, and the once plentiful 32 GiB of RAM seems smaller by the day.

While the old NAS is still capable of running my services and hosting files, the CPU (Intel Xeon E3-1231 v3) sometimes struggles when there is lots of usage. Similary, the amount of RAM is still okay, but with 50% of constant usage doesn’t leave a lot of space to grow. To remedy there issues, I wanted to upgrade the NAS with a AM5 board and CPU, but right before I was able to do so, the prices for DDR5 absulutely exploded.

As I didn’t want to spend 1200€ just for a 64 GiB DDR5 kit what only cost 180€ a couple weeks ago, I chose to buy a used Dell PowerEdge R530 instead. It already came with 64 GiB of DDR4 preinstalled, which I promptly upgraded to 128 GiB, as prices for used DDR4 server RAM is fairly manageable. While it’s a bit more power hungry than my old FreeBSD NAS, it has enough RAM and CPU power to also retire my Proxmox VE host, so here we are. However, when I first installed FreeBSD on the Dell R530, I noticed lots of write and I/O errors on the console, which lead me to write this post.

Not all LSI SAS HBA are made equally

Searching for the error messages, I found this blog post by Dan Langille, which explained the issue and a solution. It turnes out that FreeBSD needs the mrsas(4) driver for the newer Broadcom/LSI SAS HBAs, which isn’t used by default. While I was able to get an old Install of FreeBSD to run on the Dell server, I wasn’t able to boot a fresh install, as the FreeBSD installer used the old and imcompatible mfi(4) driver.

Manually setting the correct sysctl in the Installer’s shell isn’t possible, as it’s a “read only tuneable”.

hw mfi mrsas_enable

To remedy this, I decided to modify the ISO of the FreeBSD installer, so it will use the correct driver during the installation process.

Modification steps

The following steps were done on my Pop!_OS Linux desktop, because I was in a rush. If you want to do this on FreeBSD, you need to install sysutils/dvd+rw-tools to use the growisofs command (not tested).

First, the ISO installer to be modified needs to be downloaded:

wget https://download.freebsd.org/releases/amd64/amd64/ISO-IMAGES/14.3/FreeBSD-14.3-RELEASE-amd64-disc1.iso

To avoid confusion, the modified ISO file is renamed:

cp FreeBSD-14.3-RELEASE-amd64-disc1.iso FreeBSD-14.3-RELEASE-amd64-DELL.iso

Next, we install the program growisofs to modify the ISO file:

sudo apt install growisofs

Next, we read information from the ISO file and store the information in the variable volid:

volid=$(isoinfo -d -i FreeBSD-14.3-RELEASE-amd64-DELL.iso | awk '/Volume id/{print$3}')

Optional: Check whether the variable has been created correctly:

admin@pop-os:~$ echo $volid
15_0_RELEASE_AMD64_CD

Now we create the empty file loader.conf.local and store the following data in it:

touch loader.conf.local

echo 'hw.mfi.mrsas_enable="1"' > loader.conf.local

Optional: Check whether the file was populated correctly:

admin@pop-os:~$ cat loader.conf.local 
hw.mfi.mrsas_enable="1"

Next, we’ll extend our FreeBSD installer ISO file with loader.conf.local:

sudo growisofs -M FreeBSD-14.3-RELEASE-amd64-DELL.iso -d -l -r -V "$volid" -graft-points /boot/loader.conf.local=loader.conf.local

Now we can copy the resulting ISO file to a USB stick. I used the software Ventoy for this. FreeBSD can now be installed on the Dell server as usual.

Once the installation is complete, select “Yes” when promted for “Manual Configuration”:

image

Now, create the file /boot/loader.conf.local on the freh FreeBSD install:

ee /boot/loader.conf.local

Enter the following and then save + exit the file with pressing the Esc key.

hw.mfi.mrsas_enable="1"

After that, the USB stick can be removed and the server restarted — done. :)

  1. Esc
  2. a) leave editor
  3. a) save changes
  4. shutdown -r now

Before:

Screenshot from 2026-01-18 20-37-59

After:

Screenshot from 2026-01-18 20-51-24

Apparently, you can also flash the Dell PERC H330 firmware to IT mode, but I don’t think that’s necessary. This fix should also work with other Dell servers, such as the Dell PowerEdge R730, as long as it’s also using the H330.

image