The libxl driver currently sets the disk backend to
LIBXL_DISK_BACKEND_TAP when <driver name='file'> is specified
in the <disk> config. qdisk should be prefered with this
configuration, otherwise existing configuration such as the
following, which worked with the old Xen driver, will not work
with the libxl driver
<disk type='file' device='cdrom'>
<driver name='file'/>
<source file='/path/to/some/iso'/>
<target dev='hdc' bus='ide'/>
<readonly/>
</disk>
In addition, tap performs poorly compared to qdisk.
Signed-off-by: Jim Fehlig <jfehlig(a)suse.com>
---
src/libxl/libxl_conf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index fdbb522..4b6b5c0 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -796,7 +796,7 @@ libxlMakeDisk(virDomainDiskDefPtr l_disk, libxl_device_disk *x_disk)
return -1;
}
x_disk->format = LIBXL_DISK_FORMAT_RAW;
- x_disk->backend = LIBXL_DISK_BACKEND_TAP;
+ x_disk->backend = LIBXL_DISK_BACKEND_QDISK;
} else if (STREQ(driver, "phy")) {
if (format != VIR_STORAGE_FILE_NONE &&
format != VIR_STORAGE_FILE_RAW) {
--
1.8.4.5