diff --git a/daemon/libvirtd.service.in b/daemon/libvirtd.service.in
index c72dde564f..899abdf37e 100644
--- a/daemon/libvirtd.service.in
+++ b/daemon/libvirtd.service.in
@@ -24,8 +24,11 @@ ExecStart=@sbindir@/libvirtd $LIBVIRTD_ARGS
 ExecReload=/bin/kill -HUP $MAINPID
 KillMode=process
 Restart=on-failure
-# Override the maximum number of opened files
-#LimitNOFILE=2048
+# At least 1 FD per guest, often 2 (eg qemu monitor + qemu agent).
+# eg if we want to support 4096 guests, we'll typically need 8192 FDs
+# If changing this, also consider virtlogd.service & virtlockd.service
+# limits which are also related to number of guests
+LimitNOFILE=8192
 
 [Install]
 WantedBy=multi-user.target
diff --git a/src/locking/virtlockd.service.in b/src/locking/virtlockd.service.in
index 69b568f8e4..c369591267 100644
--- a/src/locking/virtlockd.service.in
+++ b/src/locking/virtlockd.service.in
@@ -13,6 +13,10 @@ ExecReload=/bin/kill -USR1 $MAINPID
 # cause the machine to be fenced (rebooted), so make
 # sure we discourage OOM killer
 OOMScoreAdjust=-900
+# Needs to allow for max guests * average disks per guest
+# libvirtd.service written to expect 4096 guests, so if we
+# allow for 4 disks per guest, we get:
+LimitNOFILE=16384
 
 [Install]
 Also=virtlockd.socket
diff --git a/src/logging/virtlogd.service.in b/src/logging/virtlogd.service.in
index 09e0740149..8b67317cb1 100644
--- a/src/logging/virtlogd.service.in
+++ b/src/logging/virtlogd.service.in
@@ -13,6 +13,11 @@ ExecReload=/bin/kill -USR1 $MAINPID
 # cause the machine to be fenced (rebooted), so make
 # sure we discourage OOM killer
 OOMScoreAdjust=-900
+# Need to have at least one file open per guest (eg QEMU
+# stdio log), but might be more (eg serial console logs)
+# libvirtd.service written to expect 4096 guests, so if we
+# guess at 2 log files per guest here (stdio + 1 serial):
+LimitNOFILE=8192
 
 [Install]
 Also=virtlogd.socket