I don't know the details well; I know the device itself supports the block-device-level cache-flush commands (I know there's a SCSI-specific one but I don't know offhand if there's a device generic one) so the guest OS can, and does, request flushing. I can't remember if there's also a qemu command to prompt the virtual device to flush without telling the guest.
On 02/04/2015 11:08 PM, Udo Lembke wrote: > Hi Dan, > I mean qemu-kvm, also librbd. > But how I can kvm told to flush the buffer? > > Udo > > On 05.02.2015 07:59, Dan Mick wrote: >> On 02/04/2015 10:44 PM, Udo Lembke wrote: >>> Hi all, >>> is there any command to flush the rbd cache like the >>> "echo 3 > /proc/sys/vm/drop_caches" for the os cache? >>> >>> Udo >> Do you mean the kernel rbd or librbd? The latter responds to flush >> requests from the hypervisor. The former...I'm not sure it has a >> separate cache. _______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
