diff --git a/qa/workunits/cephtool/test.sh b/qa/workunits/cephtool/test.sh
index f03391362e6..2d28950d162 100755
--- a/qa/workunits/cephtool/test.sh
+++ b/qa/workunits/cephtool/test.sh
@@ -360,12 +360,15 @@ function test_tiering_1()
   expect_false ceph osd tier add slow2 cache
   # test some state transitions
   ceph osd tier cache-mode cache writeback
+  # forward is removed/deprecated
   expect_false ceph osd tier cache-mode cache forward
-  ceph osd tier cache-mode cache forward --yes-i-really-mean-it
+  expect_false ceph osd tier cache-mode cache forward --yes-i-really-mean-it
   expect_false ceph osd tier cache-mode cache readonly
+  ceph osd tier cache-mode cache proxy
+  ceph osd tier cache-mode cache none
   ceph osd tier cache-mode cache readonly --yes-i-really-mean-it
   expect_false ceph osd tier cache-mode cache forward
-  ceph osd tier cache-mode cache forward --yes-i-really-mean-it
+  expect_false ceph osd tier cache-mode cache forward --yes-i-really-mean-it
   ceph osd tier cache-mode cache none
   ceph osd tier cache-mode cache writeback
   ceph osd tier cache-mode cache proxy
diff --git a/qa/workunits/rados/test_cache_pool.sh b/qa/workunits/rados/test_cache_pool.sh
index 5e28b355aba..f4187a98adf 100755
--- a/qa/workunits/rados/test_cache_pool.sh
+++ b/qa/workunits/rados/test_cache_pool.sh
@@ -137,7 +137,7 @@ rados -p base put testclone /etc/hosts
 rados -p cache cache-flush-evict-all
 rados -p cache ls - | wc -l | grep 0
 
-ceph osd tier cache-mode cache forward --yes-i-really-mean-it
+ceph osd tier cache-mode cache proxy --yes-i-really-mean-it
 rados -p base -s snap get testclone testclone.txt
 diff -q testclone.txt /etc/passwd
 rados -p base get testclone testclone.txt
diff --git a/src/mon/OSDMonitor.cc b/src/mon/OSDMonitor.cc
index 7ba9cf5cda9..86d9eb486e2 100644
--- a/src/mon/OSDMonitor.cc
+++ b/src/mon/OSDMonitor.cc
@@ -1486,6 +1486,27 @@ void OSDMonitor::encode_pending(MonitorDBStore::TransactionRef t)
 	tmp.require_osd_release >= ceph_release_t::octopus) {
       dout(10) << __func__ << " first octopus+ epoch" << dendl;
 
+      // adjust obsoleted cache modes
+      for (auto& [poolid, pi] : tmp.pools) {
+	if (pi.cache_mode == pg_pool_t::CACHEMODE_FORWARD) {
+	  if (pending_inc.new_pools.count(poolid) == 0) {
+	    pending_inc.new_pools[poolid] = pi;
+	  }
+	  dout(10) << __func__ << " switching pool " << poolid
+		   << " cachemode from forward -> proxy" << dendl;
+	  pending_inc.new_pools[poolid].cache_mode = pg_pool_t::CACHEMODE_PROXY;
+	}
+	if (pi.cache_mode == pg_pool_t::CACHEMODE_READFORWARD) {
+	  if (pending_inc.new_pools.count(poolid) == 0) {
+	    pending_inc.new_pools[poolid] = pi;
+	  }
+	  dout(10) << __func__ << " switching pool " << poolid
+		   << " cachemode from readforward -> readproxy" << dendl;
+	  pending_inc.new_pools[poolid].cache_mode =
+	    pg_pool_t::CACHEMODE_READPROXY;
+	}
+      }
+
       // clear removed_snaps for every pool
       for (auto& [poolid, pi] : tmp.pools) {
 	if (pi.removed_snaps.empty()) {
@@ -12386,6 +12407,12 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
     bool sure = false;
     cmd_getval(cct, cmdmap, "yes_i_really_mean_it", sure);
 
+    if (mode == pg_pool_t::CACHEMODE_FORWARD ||
+	mode == pg_pool_t::CACHEMODE_READFORWARD) {
+      ss << "'" << modestr << "' is no longer a supported cache mode";
+      err = -EPERM;
+      goto reply;
+    }
     if ((mode != pg_pool_t::CACHEMODE_WRITEBACK &&
 	 mode != pg_pool_t::CACHEMODE_NONE &&
 	 mode != pg_pool_t::CACHEMODE_PROXY &&
@@ -12410,10 +12437,10 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
     /* Mode description:
      *
      *  none:       No cache-mode defined
-     *  forward:    Forward all reads and writes to base pool
+     *  forward:    Forward all reads and writes to base pool [removed]
      *  writeback:  Cache writes, promote reads from base pool
      *  readonly:   Forward writes to base pool
-     *  readforward: Writes are in writeback mode, Reads are in forward mode
+     *  readforward: Writes are in writeback mode, Reads are in forward mode [removed]
      *  proxy:       Proxy all reads and writes to base pool
      *  readproxy:   Writes are in writeback mode, Reads are in proxy mode
      *
@@ -12421,10 +12448,10 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
      *
      *  none -> any
      *  forward -> proxy || readforward || readproxy || writeback || any IF num_objects_dirty == 0
-     *  proxy -> forward || readforward || readproxy || writeback || any IF num_objects_dirty == 0
+     *  proxy -> readproxy || writeback || any IF num_objects_dirty == 0
      *  readforward -> forward || proxy || readproxy || writeback || any IF num_objects_dirty == 0
-     *  readproxy -> forward || proxy || readforward || writeback || any IF num_objects_dirty == 0
-     *  writeback -> readforward || readproxy || forward || proxy
+     *  readproxy -> proxy || writeback || any IF num_objects_dirty == 0
+     *  writeback -> readproxy || proxy
      *  readonly -> any
      */
 
@@ -12433,19 +12460,13 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
     // whatever mode is on the pending state.
 
     if (p->cache_mode == pg_pool_t::CACHEMODE_WRITEBACK &&
-        (mode != pg_pool_t::CACHEMODE_FORWARD &&
-	  mode != pg_pool_t::CACHEMODE_PROXY &&
-	  mode != pg_pool_t::CACHEMODE_READFORWARD &&
+        (mode != pg_pool_t::CACHEMODE_PROXY &&
 	  mode != pg_pool_t::CACHEMODE_READPROXY)) {
       ss << "unable to set cache-mode '" << pg_pool_t::get_cache_mode_name(mode)
          << "' on a '" << pg_pool_t::get_cache_mode_name(p->cache_mode)
          << "' pool; only '"
-         << pg_pool_t::get_cache_mode_name(pg_pool_t::CACHEMODE_FORWARD)
-	 << "','"
          << pg_pool_t::get_cache_mode_name(pg_pool_t::CACHEMODE_PROXY)
 	 << "','"
-         << pg_pool_t::get_cache_mode_name(pg_pool_t::CACHEMODE_READFORWARD)
-	 << "','"
          << pg_pool_t::get_cache_mode_name(pg_pool_t::CACHEMODE_READPROXY)
         << "' allowed.";
       err = -EINVAL;
@@ -12453,25 +12474,19 @@ bool OSDMonitor::prepare_command_impl(MonOpRequestRef op,
     }
     if ((p->cache_mode == pg_pool_t::CACHEMODE_READFORWARD &&
         (mode != pg_pool_t::CACHEMODE_WRITEBACK &&
-	  mode != pg_pool_t::CACHEMODE_FORWARD &&
 	  mode != pg_pool_t::CACHEMODE_PROXY &&
 	  mode != pg_pool_t::CACHEMODE_READPROXY)) ||
 
         (p->cache_mode == pg_pool_t::CACHEMODE_READPROXY &&
         (mode != pg_pool_t::CACHEMODE_WRITEBACK &&
-	  mode != pg_pool_t::CACHEMODE_FORWARD &&
-	  mode != pg_pool_t::CACHEMODE_READFORWARD &&
 	  mode != pg_pool_t::CACHEMODE_PROXY)) ||
 
         (p->cache_mode == pg_pool_t::CACHEMODE_PROXY &&
         (mode != pg_pool_t::CACHEMODE_WRITEBACK &&
-	  mode != pg_pool_t::CACHEMODE_FORWARD &&
-	  mode != pg_pool_t::CACHEMODE_READFORWARD &&
 	  mode != pg_pool_t::CACHEMODE_READPROXY)) ||
 
         (p->cache_mode == pg_pool_t::CACHEMODE_FORWARD &&
         (mode != pg_pool_t::CACHEMODE_WRITEBACK &&
-	  mode != pg_pool_t::CACHEMODE_READFORWARD &&
 	  mode != pg_pool_t::CACHEMODE_PROXY &&
 	  mode != pg_pool_t::CACHEMODE_READPROXY))) {
 
diff --git a/src/osd/PrimaryLogPG.cc b/src/osd/PrimaryLogPG.cc
index 6b500e0eba1..9f5491616c2 100644
--- a/src/osd/PrimaryLogPG.cc
+++ b/src/osd/PrimaryLogPG.cc
@@ -2730,11 +2730,6 @@ PrimaryLogPG::cache_result_t PrimaryLogPG::maybe_handle_cache_detail(
     ceph_abort_msg("unreachable");
     return cache_result_t::NOOP;
 
-  case pg_pool_t::CACHEMODE_FORWARD:
-    // FIXME: this mode allows requests to be reordered.
-    do_cache_redirect(op);
-    return cache_result_t::HANDLED_REDIRECT;
-
   case pg_pool_t::CACHEMODE_READONLY:
     // TODO: clean this case up
     if (!obc.get() && r == -ENOENT) {
@@ -2749,23 +2744,8 @@ PrimaryLogPG::cache_result_t PrimaryLogPG::maybe_handle_cache_detail(
     // crap, there was a failure of some kind
     return cache_result_t::NOOP;
 
-  case pg_pool_t::CACHEMODE_READFORWARD:
-    // Do writeback to the cache tier for writes
-    if (op->may_write() || write_ordered || must_promote) {
-      if (agent_state &&
-	  agent_state->evict_mode == TierAgentState::EVICT_MODE_FULL) {
-	dout(20) << __func__ << " cache pool full, waiting" << dendl;
-	block_write_on_full_cache(missing_oid, op);
-	return cache_result_t::BLOCKED_FULL;
-      }
-      promote_object(obc, missing_oid, oloc, op, promote_obc);
-      return cache_result_t::BLOCKED_PROMOTE;
-    }
-
-    // If it is a read, we can read, we need to forward it
-    do_cache_redirect(op);
-    return cache_result_t::HANDLED_REDIRECT;
-
+  case pg_pool_t::CACHEMODE_FORWARD:
+    // this mode is deprecated; proxy instead
   case pg_pool_t::CACHEMODE_PROXY:
     if (!must_promote) {
       if (op->may_write() || op->may_cache() || write_ordered) {
@@ -2786,6 +2766,8 @@ PrimaryLogPG::cache_result_t PrimaryLogPG::maybe_handle_cache_detail(
     promote_object(obc, missing_oid, oloc, op, promote_obc);
     return cache_result_t::BLOCKED_PROMOTE;
 
+  case pg_pool_t::CACHEMODE_READFORWARD:
+    // this mode is deprecated; proxy instead
   case pg_pool_t::CACHEMODE_READPROXY:
     // Do writeback to the cache tier for writes
     if (op->may_write() || write_ordered || must_promote) {