https://access.redhat.com/solutions/7095289

This solution document provides and explanation for the behavior, but does not address how to manage or prevent it.

libdnf is not managing the hashed names well when the assigned content view (CV) for the host changes.

Our software release model generates new composite CVs monthly which are then assigned to instances of services based on the maintenance cycle (eg, monthly, quarterly) agreed to by the service owner. The composite CVs are comprised likewise of component CVs, all of which have name suffixes of YYYYMM.

A host on monthly cycle, for example, after a year, would have accumulated 12 directories for each component repository. From a current example host:

~~~
[root@andypupdev-casl-d09 ~]# ls -ldtr /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms*
drwxr-xr-x 3 root root 4096 Nov 13 2024 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-f8d239113d0ec16f
drwxr-xr-x 4 root root 4096 Dec 9 2024 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-7a93e9357fd422ac
drwxr-xr-x 4 root root 4096 Jan 7 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-3bf183f0180d547d
drwxr-xr-x 4 root root 4096 Feb 3 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-04c99f8a6330f0e6
drwxr-xr-x 4 root root 4096 Mar 3 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-74eeb357c4d4d3e2
drwxr-xr-x 3 root root 4096 Mar 18 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-13fbbc6c437b0a06
drwxr-xr-x 3 root root 4096 Mar 20 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-1d833e5b471e9a0d
drwxr-xr-x 4 root root 4096 Apr 7 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-4d370ecca6170b1d
drwxr-xr-x 4 root root 4096 May 12 2025 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-f92e31a7d0b9de42
drwxr-xr-x 4 root root 4096 Jun 2 10:13 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-cfad0ad1b70f0fa8
drwxr-xr-x 4 root root 4096 Jul 7 16:51 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-3085534850030d05
drwxr-xr-x 4 root root 4096 Aug 4 11:14 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-cfa3ebf60f2bab71
drwxr-xr-x 4 root root 4096 Sep 2 14:33 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-44cdec7433337d5b
drwxr-xr-x 4 root root 4096 Oct 13 05:04 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-1a15b80652dc8d89
rw-rr- 1 root root 7530649 Nov 10 05:03 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-filenames.solvx
rw-rr- 1 root root 2755733 Nov 10 05:03 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-updateinfo.solvx
rw-rr- 1 root root 13658423 Nov 10 05:03 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms.solv
drwxr-xr-x 4 root root 4096 Nov 10 05:03 /var/cache/dnf/rhel-9-for-x86_64-baseos-rpms-6e7de7a1e8cec2c5
~~~

dnf should do a better job to keep this clutter from being generated.