diff --git a/.build/docker/_copy_ccm_repositories.sh b/.build/docker/_copy_ccm_repositories.sh
new file mode 100755
index 0000000000..7515211e23
--- /dev/null
+++ b/.build/docker/_copy_ccm_repositories.sh
@@ -0,0 +1,51 @@
+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+################################
+#
+# Prep
+#
+################################
+
+if [ "$1" == "-h" ]; then
+   echo "$0 [-h]"
+   echo " this script is used internally by other scripts in the same directory to copy the image's ccm repositories into the dtest tmpdir"
+   exit 1
+fi
+
+command -v rsync >/dev/null 2>&1 || { echo >&2 "rsync needs to be installed"; exit 1; }
+
+################################
+#
+# Main
+#
+################################
+
+
+# prepopulate a tmp ccm repository directory from whats already in the image
+#
+# the image has all versions and branches in ~/.ccm/repository already
+# the container doesn't re-use ~/.ccm/repository so to avoid any writes in the containerfs
+# so we rsync what's important from ~/.ccm/repository to the configured ${CCM_CONFIG_DIR}
+# this appears to take a long time, but should be faster than ccm downloading
+# rsync is used as it's the friendlier approach against open file ulimits
+echo -n "prepopulating ${CCM_CONFIG_DIR}/repository/ for upgrade tests…"
+mkdir -p "${CCM_CONFIG_DIR}/repository/"
+rsync -rptgoL --include '[1-9]*' ${HOME}/.ccm/repository ${CCM_CONFIG_DIR}/
+rsync -rptgoL --include '_git_cache_apache' ${HOME}/.ccm/repository ${CCM_CONFIG_DIR}/
+rsync -rptgoL --include 'gitCOLON*' ${HOME}/.ccm/repository ${CCM_CONFIG_DIR}/
+echo " complete"
diff --git a/.build/docker/run-tests.sh b/.build/docker/run-tests.sh
index 34b17fc4e9..9221fbff97 100755
--- a/.build/docker/run-tests.sh
+++ b/.build/docker/run-tests.sh
@@ -189,6 +189,8 @@ chmod -R ag+rwx "${build_dir}"
 case "${target}" in
     "cqlsh-test" | "dtest" | "dtest-novnode" | "dtest-latest" | "dtest-large" | "dtest-large-novnode" | "dtest-upgrade" | "dtest-upgrade-large" | "dtest-upgrade-novnode" | "dtest-upgrade-novnode-large" )
         ANT_OPTS="-Dtesttag.extra=_$(arch)_python${python_version/./-}"
+        # intentionally not TMP_DIR
+        DTEST_TMPDIR_LOCAL="$(mktemp -d ${build_dir}/run-python-dtest.XXXXXX)"
     ;;
     "jvm-dtest-novnode" | "jvm-dtest-upgrade-novnode" )
         ANT_OPTS="-Dtesttag.extra=_$(arch)_novnode"
@@ -208,6 +210,10 @@ fi
 
 # the docker container's env
 docker_envs="--env TEST_SCRIPT=${test_script} --env JAVA_VERSION=${java_version} --env PYTHON_VERSION=${python_version} --env cython=${cython} --env ANT_OPTS=\"${ANT_OPTS}\""
+if [ -n "${DTEST_TMPDIR_LOCAL}" ] ; then
+    DTEST_TMPDIR_REMOTE="$(sed "s:${build_dir}:/home/cassandra/cassandra/build:" <<< ${DTEST_TMPDIR_LOCAL})"
+    docker_envs="${docker_envs} --env TMPDIR=${DTEST_TMPDIR_REMOTE} --env CCM_CONFIG_DIR=${DTEST_TMPDIR_REMOTE}/.ccm"
+fi
 [ $DEBUG ] && docker_envs="${docker_envs} --env DEBUG=1"
 
 split_str="0_0"
@@ -241,6 +247,12 @@ echo "Running container ${container_name} ${docker_id}"
 docker exec --user root ${container_name} bash -c "\${CASSANDRA_DIR}/.build/docker/_create_user.sh cassandra $(id -u) $(id -g)" | tee -a ${logfile}
 docker exec --user root ${container_name} update-alternatives --set python /usr/bin/python${python_version} | tee -a ${logfile}
 
+if [ -n "${DTEST_TMPDIR_LOCAL}" ] && [[ "${target}" =~ ^dtest-upgrade ]] ; then
+    # prepopulate a tmp ccm repository directory, if running dtest-upgrade tests
+    docker exec --user cassandra ${container_name} bash -c "\${CASSANDRA_DIR}/.build/docker/_copy_ccm_repositories.sh" | tee -a ${logfile}
+    trap 'nohup rm -rf "${DTEST_TMPDIR_LOCAL}/.ccm/repository" >/dev/null 2>&1 &' EXIT
+fi
+
 # capture logs and status
 set -o pipefail
 docker exec --user cassandra ${container_name} bash -c "${docker_command}" | tee -a ${logfile}
@@ -266,5 +278,5 @@ xz -f ${logfile} 2>/dev/null
 
 popd >/dev/null
 popd >/dev/null
-set -x
+echo "+ exit ${status}"
 exit ${status}
diff --git a/.build/docker/ubuntu2004_test.docker b/.build/docker/ubuntu2004_test.docker
index e55edf9b84..2c93719a35 100644
--- a/.build/docker/ubuntu2004_test.docker
+++ b/.build/docker/ubuntu2004_test.docker
@@ -51,7 +51,7 @@ RUN export DEBIAN_FRONTEND=noninteractive && \
         python3.8 python3.8-venv python3.8-dev \
         python3.11 python3.11-venv python3.11-dev \
         virtualenv net-tools libev4 libev-dev wget gcc libxml2 libxslt1-dev \
-        vim lsof sudo libjemalloc2 dumb-init locales \
+        vim lsof sudo libjemalloc2 dumb-init locales rsync \
         openjdk-8-jdk openjdk-11-jdk openjdk-17-jdk ant ant-optional
 
 
diff --git a/.build/run-python-dtests.sh b/.build/run-python-dtests.sh
index 8a6995dcfb..80e15e8b73 100755
--- a/.build/run-python-dtests.sh
+++ b/.build/run-python-dtests.sh
@@ -43,19 +43,19 @@ DTEST_SPLIT_CHUNK="$2"
 
 # variables, with defaults
 [ "x${CASSANDRA_DIR}" != "x" ] || CASSANDRA_DIR="$(readlink -f $(dirname "$0")/..)"
-[ "x${CASSANDRA_DTEST_DIR}" != "x" ] || CASSANDRA_DTEST_DIR="${CASSANDRA_DIR}/../cassandra-dtest"
+[ "x${CASSANDRA_DTEST_DIR}" != "x" ] || CASSANDRA_DTEST_DIR="$(readlink -f ${CASSANDRA_DIR}/../cassandra-dtest)"
 [ "x${DIST_DIR}" != "x" ] || DIST_DIR="${CASSANDRA_DIR}/build"
+[ "x${TMPDIR}" != "x" ] || { TMPDIR_SET=1 && export TMPDIR="$(mktemp -d ${DIST_DIR}/run-python-dtest.XXXXXX)" ; }
+[ "x${CCM_CONFIG_DIR}" != "x" ] && ls $CCM_CONFIG_DIR
 
-export TMPDIR="$(mktemp -d ${DIST_DIR}/run-python-dtest.XXXXXX)"
 export PYTHONIOENCODING="utf-8"
 export PYTHONUNBUFFERED=true
 export CASS_DRIVER_NO_EXTENSIONS=true
 export CASS_DRIVER_NO_CYTHON=true
 export CCM_MAX_HEAP_SIZE="1024M"
 export CCM_HEAP_NEWSIZE="512M"
-export CCM_CONFIG_DIR="${TMPDIR}/.ccm"
 export NUM_TOKENS="16"
-#Have Cassandra skip all fsyncs to improve test performance and reliability
+# Have Cassandra skip all fsyncs to improve test performance and reliability
 export CASSANDRA_SKIP_SYNC=true
 unset CASSANDRA_HOME
 
@@ -146,6 +146,12 @@ if [[ "${DTEST_SPLIT_CHUNK}" =~ ^[0-9]+/[0-9]+$ ]]; then
     ( split --help 2>&1 ) | grep -q "r/K/N" || split_cmd=gsplit
     command -v ${split_cmd} >/dev/null 2>&1 || { echo >&2 "${split_cmd} needs to be installed"; exit 1; }
     SPLIT_TESTS=$(${split_cmd} -n r/${DTEST_SPLIT_CHUNK} ${DIST_DIR}/test_list.txt)
+    if [[ -z "${SPLIT_TESTS}" ]]; then
+      # something has to run in the split to generate a nosetest xml result (and to not rerun all tests)
+      echo "Hacking ${DTEST_TARGET} to run only first test found as no tests in split ${DTEST_SPLIT_CHUNK} were found: "
+      SPLIT_TESTS="$( echo ${DIST_DIR}/test_list.txt | head -n1)"
+      echo "  ${SPLIT_TESTS}"
+    fi
     SPLIT_STRING="_${DTEST_SPLIT_CHUNK//\//_}"
 elif [[ "x" != "x${DTEST_SPLIT_CHUNK}" ]] ; then
     SPLIT_TESTS=$(grep -e "${DTEST_SPLIT_CHUNK}" ${DIST_DIR}/test_list.txt)
@@ -182,8 +188,10 @@ popd  >/dev/null
 #
 ################################
 
-[[ "${TMPDIR}" == *"${DIST_DIR}/run-python-dtest."* ]] && rm -rf "${TMPDIR}"
-unset TMPDIR
+if [ ${TMPDIR_SET} ] ; then
+    [[ "${TMPDIR}" == *"${DIST_DIR}/run-python-dtest."* ]] && rm -rf "${TMPDIR}"
+    unset TMPDIR
+fi
 deactivate
 
 # Exit cleanly for usable "Unstable" status
diff --git a/.jenkins/Jenkinsfile b/.jenkins/Jenkinsfile
index b0315c04f6..e44c2b31d4 100644
--- a/.jenkins/Jenkinsfile
+++ b/.jenkins/Jenkinsfile
@@ -178,8 +178,8 @@ def tasks() {
     'dtest-large-novnode': [splits: 8, size: 'large'],
     'dtest-upgrade': [splits: 64, size: 'large'],
     'dtest-upgrade-novnode': [splits: 64, size: 'large'],
-    'dtest-upgrade-large': [splits: 64, size: 'large'],
-    'dtest-upgrade-novnode-large': [splits: 64, size: 'large'],
+    'dtest-upgrade-large': [splits: 32, size: 'large'],
+    'dtest-upgrade-novnode-large': [splits: 32, size: 'large'],
   ]
   testSteps.each() {
     it.value.put('type', 'test')