Re: [libvirt] How to detect if qemu supports discard?

On Sun, Mar 09, 2014 at 03:23:25PM +0000, Richard W.M. Jones wrote: > from src/qemu/qemu_command.c: > > if (disk->discard) { > if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DRIVE_DISCARD)) { > virBufferAsprintf(&opt, ",discard=%s", > virDomainDiskDiscardTypeToString(disk->discard)); > } else { > virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", > _("discard is not supported by this QEMU binary")); > goto error; > } > } > > However there appears to be no way to tell programmatically if the > qemu binary supports discard (ie. via libvirt). Therefore libguestfs > can never know when it is safe to use this option in the XML. > Many of these requests/issues are appearing lately. Can we dump qemu caps with normal capablities with e.g. "virsh capabilities --verbose"? We have to keep the strings used consitent anyway since it's used in migration data and so on.