Selfhosted

I don't know of a pre-wrapped utility to do that, but assuming that this is a Linux system, here's a simple bash script that'd do it.

#!/bin/bash

# Set this.  Path to a new, not-yet-existing directory that will retain a copy of a list
# of your files.  You probably don't actually want this in /tmp, or
# it'll be wiped on reboot.

file_list_location=/tmp/storage-history

# Set this.  Path to location with files that you want to monitor.

path_to_monitor=path-to-monitor

# If the file list location doesn't yet exist, create it.
if [[ ! -d "$file_list_location" ]]; then
    mkdir "$file_list_location"
    git -C "$file_list_location" init
fi

# in case someone's checked out things at a different time
git -C "$file_list_location" checkout master
find "$path_to_monitor"|sort>"$file_list_location/files.txt"
git -C "$file_list_location" add "$file_list_location/files.txt"
git -C "$file_list_location" commit -m "Updated file list for $(date)"

That'll drop a text file at /tmp/storage-history/files.txt with a list of the files at that location, and create a git repo at /tmp/storage-history that will contain a history of that file.

When your drive array kerplodes or something, your files.txt file will probably become empty if the mount goes away, but you'll have a git repository containing a full history of your list of files, so you can go back to a list of the files there as they existed at any historical date.

Run that script nightly out of your crontab or something ($ crontab -e to edit your crontab).

As the script says, you need to choose a file_list_location (not /tmp, since that'll be wiped on reboot), and set path_to_monitor to wherever the tree of files is that you want to keep track of (like, /mnt/file_array or whatever).

You could save a bit of space by adding a line at the end to remove the current files.txt after generating the current git commit if you want. The next run will just regenerate files.txt anyway, and you can just use git to regenerate a copy of the file at for any historical day you want. If you're not familiar with git, $ git log to find the hashref for a given day, $ git checkout <hashref> to move where things were on that day.

EDIT: Moved the git checkout up.