Trying to set any cache for <disk device='lun'/> makes no sense. Such disk translates into -device scsi-block on the command line and the device lacks any cache setting because it's merely a middle man between qemu and real SCSI device. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_command.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 7408f6bc70..c7ff074e29 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -1824,6 +1824,11 @@ qemuBuildDriveDevCacheStr(virDomainDiskDefPtr disk, if (disk->cachemode == VIR_DOMAIN_DISK_CACHE_DEFAULT) return 0; + /* VIR_DOMAIN_DISK_DEVICE_LUN translates into 'scsi-block' + * where any caching setting makes no sense. */ + if (disk->device == VIR_DOMAIN_DISK_DEVICE_LUN) + return 0; + if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DISK_WRITE_CACHE)) return 0; -- 2.16.1