libvirt-guests is a perfect use case for O_DIRECT - lots of filesystem
traffic done at system shutdown, where caching is pointless, and
startup, where caching gets in the way. Make this a configurable
option in the init script, but defaulting to existing behavior.
* tools/libvirt-guests.sysconf (SAVE_DIRECT): New variable.
* tools/libvirt-guests.init.sh (suspend_guest): Use it.
---
tools/libvirt-guests.init.sh | 5 ++++-
tools/libvirt-guests.sysconf | 4 ++++
2 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/tools/libvirt-guests.init.sh b/tools/libvirt-guests.init.sh
index 30f957a..4e383c4 100644
--- a/tools/libvirt-guests.init.sh
+++ b/tools/libvirt-guests.init.sh
@@ -43,6 +43,7 @@ ON_BOOT=start
ON_SHUTDOWN=suspend
SHUTDOWN_TIMEOUT=0
START_DELAY=0
+SAVE_DIRECT=0
test -f "$sysconfdir"/sysconfig/libvirt-guests &&
. "$sysconfdir"/sysconfig/libvirt-guests
@@ -190,8 +191,10 @@ suspend_guest()
name=$(guest_name "$uri" "$guest")
label=$(eval_gettext "Suspending \$name: ")
+ direct=
+ test "x$SAVE_DIRECT" = x0 || direct=--direct
printf %s "$label"
- run_virsh "$uri" managedsave "$guest" >/dev/null &
+ run_virsh "$uri" managedsave "$direct" "$guest" >/dev/null &
virsh_pid=$!
while true; do
sleep 1
diff --git a/tools/libvirt-guests.sysconf b/tools/libvirt-guests.sysconf
index 37b258e..da465ad 100644
--- a/tools/libvirt-guests.sysconf
+++ b/tools/libvirt-guests.sysconf
@@ -25,3 +25,7 @@
# number of seconds we're willing to wait for a guest to shut down
#SHUTDOWN_TIMEOUT=0
+
+# If non-zero, try to use O_DIRECT when saving and restoring guests,
+# for less filesystem cache pollution, but possibly slower operation.
+#SAVE_DIRECT=0
--
1.7.4.4
--
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